Have any of you tried the new
Reverb 4 from Toneboosters? It does 6 channel (5.1) and to my ear sounds quite good. At 30 Euro it's a pretty good deal too.
I'm going to do a little digging to find out what it does with the C and LFE channels, it seems from my initial usage of it on first order ambisonic signal that it must treat all input signals as discrete and non-unique assuming an ITU L,R,C,LFE,Ls,Rs channel order.