here's how the two teams rank overall at different strengths:
gf/a60 = goals for/against per 60
xgf/a60 = expected goals for/against per 60
sh/v% = shooting/save percentage
fsh/v% = fenwick shooting/save percentage
xfsh/sv% = expected shooting/save percentage
pdo = save + shooting percentage
xpdo = expected save + shooting percentage
Numbers from Corsica.hockey, with Score/Venue adjustments.
5v5 Even Strength
Offense
WSH 2.79gf60 (#3), 2.59xgf60 (#11), 9.17sh% (#2), 6.60fsh% (#2), 5.97xfsh% (#14)
TOR 2.61gf60 (#5), 2.86xgf60 (#2), 8.33sh% (#8), 5.75fsh% (#11), 6.26xfsh% (#5)
Both teams with elite offenses. The Leafs seem to produce better offense in terms of chances but the Caps have had better finish - and while the Caps may have earned their "luck" in exceeding their expected shooting percentage with pure skill, by the same token the leafs' pure skill is good enough that their underachieveing shooting percentage is probably a bit lucky.
Defense
WSH 1.73ga60 (#1), 2.35xga60 (#7), 93.73sv% (#1), 95.59fsv% (#1), 93.92xfsv% (#20)
TOR 2.46ga60 (#23), 2.65xga60 (#26), 92.29sv% (#18), 94.57fsv% (#13), 94.12xfsv% (#11)
Washington has been good defensively, but have received outright dominant goaltending at even strength. Leafs have been poor defensively with mediocre goaltending at even strength.
Overall
WSH 61.75gf% (#1), 52.40xgf% (#7), 102.90pdo (#1), 99.90xpdo (#19)
TOR 51.47gf% (#13), 51.87xgf% (#9), 100.62pdo (#12), 100.38xpdo (#3)
The two groups of skaters have arguably performed quite similarly overall at even strength, but with a solid advantage to Washington in shooting percentage, and an even bigger one in goaltending. Based on their expected pdo, it looks like the leafs have been a bit unlucky at even strength given their quality play.
5v4 Power Play
WSH 7.40gf60 (#4), 6.73xgf60 (#7), 14.73sh% (#4), 9.89fsh% (#10), 9.00xfsh% (#16)
TOR 7.46gf60 (#3), 7.50xgf60 (#1), 14.13sg% (#7), 9.98fsh% (#9), 10.03xfsh% (#3)
Both have dominant PPs, though again the leafs seem to be a bit unlucky shooting percentage wise given their raw skill.
4v5 Penalty Kill
WSH 5.16ga60 (#8), 5.24xga60 (#6), 85.52sv% (#26), 90.55fsv% (#20), 90.40xfsv% (#25)
TOR 5.30ga60 (#9), 6.63xga60 (#23), 89.43sv% (#3), 92.64fsv% (#3), 90.80xfsv% (#19)
Both have very solid penalty kills, but in this case the script flips from what it was at even strength - the Leafs have received great goaltending on the PK while the caps' have not. It's really hard to tell if this means anything, but it's an interesting difference from even strength.