going direct using cabinet simulator pedals

OK, I need some schooling regarding cabinet simulator pedals. I'm thinking seriously about going direct to mixer/PA for this one project I'm involved in. I love my pedals too much to go the POD route, and I'm not interested in the rack stuff. (Yet, anyway. This IS TGP, after all.)

OK, so a lot of folks like the Tech 21 'character" pedals. Can you go straight to the board with these last in your chain?

These are the others on my radar:

New ADA cab sim pedal -- pretty inexpensive at $120
Radial JDX - basically direct box for electric guitar
Torpedo C.A.B. -- lots of cabs in there but >$500

I'm also confused about "pre-amp" pedals versus regular OD pedals -- the marketing stuff for the above products seems to indicate they all take regular guitar and pedal signals and make them work for a direct input to a mixing board, but then I've seen conflicting stuff that you really need pre-amp type pedals.

I guess the main question is how do all these sound? How are you guys that go direct do it?

Thanks!