I try to make balanced, all-comers lists, and I tend to want to play against players who are close to my skill level. In the last tournament I played in with my mech Guard, I smashed my first opponent, pulled a win out of my ass against my second opponent, and nearly fought my third opponent to a stand-still (tied on objectives, went to KP tie-breaker where I lost).
But then during a normal game last week, I was tabled on turn 7 :D
I guess my experience is that as long as I'm not playing against complete scrubs, I have plenty of close games, which are the most fun to me, though sometimes things go wonky and the game becomes a blow-out, but that seems to be the exception rather than the rule.