Wow. Really? My guys can't stand the Daredevil or the Infiltrator. The Daredevil is pretty much referred to as "the ability score-boosting advanced class", as that was about the only thing people saw as a reason to take it. Everything else was stuff that most other classes could do or approximate, or abilities that just didn't stand out enough. (I can't really confirm this, as nobody voluntarily played one in a game.)
And the Infiltrator just didn't have enough flash for my guys -- improvised weapons don't really work that well with that Smart Hero BAB, and not enough real coolness that made you noticeably better at infiltrating. I think they wanted something like a "Hide in Plain Sight" ability -- spend an action point to hang from the ceiling while guards walk by underneath you or something cool like that -- or class improvements to Knockout Punch that made the Infiltrator a good sneak-attacker (or even getting Sneak Attack, for that matter). They just didn't think it got enough in the way of things that they would use, and that weren't effectively duplicated by skills and feats.
Again, curious, not arguing. Everybody's game is different, and I might well have made a game for which those two classes just didn't fit.