I suspect for most, sensitivity probably trumps accuracy, which is to say your ability to acquire and track a location in difficult conditions (forest cover, canyons) is more important than whether you know your location to one meter or just ten meters.
Newer units seem to have traded sensitive antennas for more channels and speedier processing. Whether that's a good thing I'll leave to the experts. What I see in field comparisons is that some units can cold fix on the move in the woods while others just sit there, searching. Most seem to be able to track me once they acquire a fix, which is a notable improvement from my earliest experiences.
If I sit in one place long enough, they all eventually narrow my location to within ten or so feet, given enough satellites plus WAAS reception. This is most noticable with elevation, which can take quite awhile to match a known height.
I've mostly used a PN60 and an Oregon 450 lately. The Oregon might have a sensitivity edge, plus the larger display. They're both far better than my eTrex Legend CX (except in battery life).