The most fascinating part about the American League Championship Series between the Red Sox and Astros isn't that they won 100-plus games, or that they faced off in the AL Division Series last season, when Houston won 3-1 on its way to its first World Series title.
It's that the Red Sox won 108 games, the best in team history, they dispatched the 100-win Yankees in the ALDS ... and it almost feels like they're the underdog here. After all, the Astros won 103 games, they're the defending World Series champs, and it certainly feels like the 2018 version is better than the '17 edition.
:: ALCS schedule and results ::
That doesn't mean it's OK to look past Boston, obviously. Let's check out these two superpowers, position by position.
Catcher
This spot isn't a strength for either team, really, but Sandy Leon (.177/.232/.279) and Christian Vazquez (.207/.257/.283) were very literally the two weakest semi-regular hitters in baseball this year. They add value on defense (Leon's +11 runs saved via framing was a top-10 mark), yet it's difficult to look past their total lack of offense. (Third catcher Blake Swihart's .229/.285/.328 line was somehow the best of the three.)
Houston's Martin Maldonado (.225/.276/.351) and Brian McCann (.212/.301/.339) aren't exactly lighting up the scoreboard themselves, but they're at least slightly more competent at the plate, and Maldonado's 87.5 mph average arm strength is baseball's third-best among catchers. 
Small advantage: Astros
First Base
Yuli Gurriel (.291/.323/.428) is fine, but an MLB-average hitter at first base doesn't really stand out. (On a rate basis, he was the 15th-best hitting first baseman among qualified players.) For Boston, Mitch Moreland followed a strong first half (.278/.353/.500) with a dreadful second half (.191/.277/.322) and a postseason hamstring issue, but he's been aided by Steve Pearce (.284/.378/.512), who may be likely to get most of the playing time in the ALCS, especially against lefties. As a platoon, they're an effective partnership, but Pearce is the better slugger than Gurriel either way.
Small advantage: Red Sox
Second Base
Jose Altuve (.315/.384/.449) had more of a "very good season" than the MVP year he put up in 2017, but he's still playing at a high level, and certainly better than 36-year-old Ian Kinsler, who hit just .240/.301/.380 this year and worse (.242/.294/.311) since joining Boston. That's an obvious edge for Houston, but keep an eye out for utility player Brock Holt, who has very literally been one of the best hitters in baseball for the last two months, and he could be the primary starter against the righty-heavy Astros rotation.
Advantage: Astros

Shortstop
When they're each at their peak, you'd probably take Carlos Correa over Xander Bogaerts, but it's very clear that Correa isn't at his peak, despite his Game 3 home run in the ALDS -- which was his only hit of the series. On the season, Correa's .239/.323/.405 line was disappointingly MLB-average, and it was even worse (.180/.261/.256) in 153 plate appearances after returning from a six-week absence due to a back injury. Bogaerts, meanwhile, had a strong rebound year (.288/.360/.522) from a down 2017. 
Advantage: Red Sox

Third Base
Rafael Devers (.240/.293/.433) had an injury-plagued first full season, missing time due to shoulder and hamstring issues and losing playing time to Holt and Eduardo Nunez (.265/.289/.388) late in the year. Neither Devers nor Nunez is a strong option right now, but it also doesn't matter so much here, because neither one was ever going to match the production of Alex Bregman (.286/.394/.532 with 31 home runs), who has blossomed into a superstar this year. He showed almost no splits against lefties or righties, or even in the first half against the second. Despite all the star power in the Houston lineup, he might be their most dangerous bat right now.
Big advantage: Astros

Left Field
In some sense, this comes down to what version of Marwin Gonzalez we're going to see. His 2018 (.247/.324/.409) was a huge step back from his breakout 2017 (.303/.377/.530), making him essentially a league-average bat. Then again, some of that was driven by a poor first half preceding a good second half (.275/.352/.492), so he might be better than that season line. Andrew Benintendi (.290/.366/.465 with 16 home runs and 21 steals) had something of the opposite problem, as he hit only two of those homers in the second half. Benintendi had the better overall season, and that matters, but watch this closely in the ALCS.
Tiny advantage: Red Sox

Center Field
On the surface, this isn't close. George Springer (.265/.346/.434, with 22 home runs) out-hit Jackie Bradley Jr. (.234/.314/.403, with 13 home runs) in just about every important way, and crushed three homers in the ALDS, following his six from last October. But Bradley is a better defender, and his 50 percent hard-hit rate was much better than Springer's 37 percent, and his second half (.269/.340/.487) was much stronger than his first half (.210/.297/.345). Springer is the better player having the better year, but this is closer than you think.
Advantage: Astros

Right Field
Josh Reddick is a solid player despite a disappointing .210/.297/.345 year and ... you know what, it doesn't matter. Mookie Betts just crushed 32 homers, stole 30 bases, played elite defense, and hit .346/.438/.640. Despite the strong arguments for Michael Trout, Betts is going to dominate the AL Most Valuable Player Award balloting. He's one of the two best players in baseball at worst, and he just put up a historically good year. Almost no one can compare to that.
Big advantage: Red Sox

Designated Hitter
Let's take a brief moment to point out that Tyler White hit a strong .276/.354/.533 for Houston, and that Evan Gattis and Tony Kemp each had their moments, and that it absolutely does not matter because J.D. Martinez (.330/.402/.629 with 43 home runs) is one of the four or five most feared hitters on the planet. He'd give Boston the edge against any other DH in the game.
Big advantage: Red Sox

Starting Pitchers
Back in May, we were all wondering if we were watching a historically good Astros staff. (At season's end, its 3.11 ERA was 24 percent better than the MLB average, tying them for the third-best performance in the seven decades since baseball integrated in 1947.) Houston starters allowed baseball's lowest rotation slugging percentage (.360) and second-lowest on-base percentage (.285), while striking out a higher rate of batters (28 percent) than any other rotation. This group, which in the playoffs will be Justin Verlander, Gerrit Cole, Dallas Keuchel and Charlie Morton, is so, so good.
That's not to say the Red Sox starters aren't good, of course, because Chris Sale continues to be one of the truly elite pitchers in the game, and David Price had a better season (3.58 ERA) than you may think. Even if you don't care about his postseason struggles, however, a quartet of Sale, Price, Nathan Eovaldi, and Rick Porcello is a good group, being compared to a great one. 
Advantage: Astros

Relief Pitchers
Speaking of elite groups, the Houston relievers were tops in baseball in ERA, batting average, on-base percentage, and walk rate; they were second in strikeout rate and slugging percentage. They actually have more relievers than they know what to do with, believe it or not, since starter Lance McCullers is operating out of the bullpen, Thomas Pressly and Roberto Osuna were added via trade, and rookie flamethrower Josh James forced his way onto the roster. In the ALDS, they couldn't even find roster room for 2017 postseason heroes Brad Peacock and Chris Devenski, or Hector Rondon, who had a 3.20 ERA and struck out 67 in 59 innings this year.
(Pressly in particular has been dominant; since arriving in a trade from Minnesota, he's whiffed 35 while allowing only four walks and two runs, including the ALDS.)
The Red Sox have Craig Kimbrel, who still misses bats at an elite rate, and the foursome of Ryan Brasier, Joe Kelly, Matt Barnes, and Richard Hembree did combine for 9 2/3 innings of scoreless ball against the Yankees. But they also struck out barely more than they walked (eight to six), Kimbrel struggled to finish off the Yankees in Game 4, and the Boston bullpen was a significant source of concern heading into October. Like in the rotation, this is a good group that can't compare to Houston's outstanding group.
Big advantage: Astros

Prediction
The Red Sox are a fantastically good team, obviously, as evidenced by their 108 wins and beating the 100-win Yankees in the ALDS. But with the open questions about Price and the bullpen, and perhaps more so due to the increasing evidence that the Astros are simply baseball's best team, we'll take Houston in 6.