I've been doing iem only gigs for years.
The mxr m80/81 is great, transparent, and the eq can be incredibly useful.
The hartke bass attack is good, and works really well. It has the classic hartke sound on tap, and has an effects loop too.
Behringer make a clone of the sansamp bddi, it's pretty good as long as you can get on with the ampeg tone.
Edens wtdi is great but the gain is VERY sensitive.
I own all of these and have used them all in anger. My first choice is always my mxr m80. Very versatile, and has a separate drive channel, which can sound awesome with judicious use of the blend control