I had a set in my '98 Civic, and loved them. In fact, I'm in the market for another set for my Accord.
However, they could definitely benefit from a few simple tweaks. The ABS they're made out of could be a few mils thicker, and they could come with some sound deadening on the back.
Also, if you're the fabrictor-type, if you're able to seal the back side, they'd sound even better.
As far as getting in the way, it took me about 3 days to get used to them. I lost the dead pedal in my Civic when I installed them, but it really didn't bother me that much.
But I'll agree with FCM and say that they're a catch-all for dirt & grime, especially when your passengers can't seem to remember that there are speakers on the floor.
=W=