I play both types of leagues. H2H is like the NFL playoffs. The only thing that matters in H2H is getting into the tournament, and getting hot at the end. In Roto, that 12 ER start by Burnett in May will kill you. In H2H, you can dominate all year long and have a moth fly in Holliday's ear during the playoffs and be screwed. Generally you can coast in H2H, and really crank it up at the end when playoffs start.
Draft hitters and power early and often and dominate the batting stats. You can get into the playoffs with a mediocre pitching staff and simply "game" them by streaming good matchups, playing splits, changing strategy on the fly using 6 RP, etc. I like H2H because you can look at your opponent's roster and try to figure out a way to defeat it using your league settings and optimum roster composition at that time. For this reason, I always draft hitters early in H2H. They are the most constant commodity in fantasy.