I'm listening to a pair of Superflys with an F3 clone as I type this and its damn good. You should be able to pick one up between $500 and $600 here when they come up and I strongly suggest you do to assess it for yourself. They re-sell easily if you don't like it and you've got nothing to lose.
This F3 along with a Redgum RGi120 (integrated) are the two solid state standouts I've found for Zu speakers. I'm driving my F3 clone with a Shindo pre and the presentation is very similar to my 845 SET monos. Not sure I'd know which was playing if blindfolded--it really is SS that sounds like SET.
The Redgum makes for an exceptional, energetic synergy as well. Not quite the level of refinement of the Shindo/845 or F3 combos, but dripping wet, nicely textured and with awesome bass and drive.
I've got a Redgum RGi35 sitting on my dining table that I've been meaning to compare to my buddy's RGi120 (also on my table) and contrast the 2 against the F3 for my summer amp duties (845s too hot), but since the F3 has gotten here I haven't had much interest in pulling it out to A/B.
Someone on AC said that Mini-Torii was highly recommended by one of the Zu boys and has an exceptional synergy with the Omens. I haven't heard it, but my interest is piqued in that amp. I was strongly tempted to buy the used one on AC to demo for myself, but I've got four amps on hand at the moment and there has to be SOME end to my wife's patience with me, lol.