NI Reaktor or Access Virus b? Options

[3DMC]

I'm about to make a MAJOR change in my studio, moving from ROMplers to a synthesizer/sampler setup. I have an XP-80 that I'm selling because I'd like to move away from preset sounds. I have a Yamaha A4000 to take care of the sampling side of things, so now I need a wicked synth.
The two choices I've narrowed it down to are NI Reaktor 3 (and beefing up my Mac) or an Access Virus b. I know these are two very different beasts. I realize that the Virus has better live/realtime control (all those knobs!) and that Reaktor has more overall flexibility.

I would like opinions on the 'sound' of these two beasts from people who've used both. Any helpful opinions or suggestions are appreciated.