I'm afraid I haven't used it much, but this thread compares the RC-300 to an EHX. It's a different model, but I believe it's similar to the 2880. They look very alike.http://www.vguitarforums.com/smf/index.php?topic=11005.0
The RC-300 is very much designed as a foot control unit, but as you've noticed, it also does just fine on a table and in many ways is more feature-rich that way (it can be done, but it's a little difficult to change the volume faders with your toes!).
If you really want the best of the RC-on-the-table experience, you want an RC-505 or the smaller 202. On paper it's more powerful than the 300, but it's clumsy if you need very much foot control (even with pedal extensions).
An RC-50 is basically an older version of the RC-300. It's pretty good too, but in most ways the 300 is better. There are a few minor advantages over the 300, but not many. If you want that write-up, go here: http://www.vguitarforums.com/smf/index.php?topic=7269.0
Basically, the breakdown is something like this...
Independent foot control:
-- RC-300, or RC-50 (older model).
-- Boomerang series
Table-top control (plus some footswitch help if needed)
-- RC-505 or 202
-- EHX series
-- RC-300 is designed as a foot controller, but can be used quite well this way too
There's lots of other units as well but I think those are the most popular ones in these parts. Hopefully that gives you some ideas.