Which Zu for you

I just bought a pair of Omen bookshelf speakers from Zu and scored a pair of HSU subs on Agon. I am still in the process of putting things together, but I think it is going to be a killer system. I think this might be a cost effective way to get into Zu, for you
I also own a pair of Zu Union speakers which I switch between my Vandy 3a sigs.
 The Union were a short run model that, I think, evolved into the Soul and Omen series. They sound pretty nice by themselves, but definitely need subs, if you want the full effect.
There are a few Zu's for sale on Agon right now. I know there is someone on Agon with Omen Bookshelves, but he wants to sell them with stands (-let me know if you want his name). If you do buy used, I would avoid the models with the ribbon tweeters, as they never seemed to catch on.
As far as power amps, I found a McCormack Micro Amp for my little system. More than enough for the Zu's. You can drive them with tubes since they are so efficient, so the choices are endless.

Sean and Phil (213cobra) always give sound advice - including selection among the range of Zu speakers. Zu speakers are designed not only at different price points, but for different listening conditions and environments. 

Yes, they do. I can't give enough thanks to Sean. He emailed me back and forth with advice even though it was about a used pair of speakers, and he had nothing to gain.  Zu really is one of the best companies out there. Seriously amazing product combined with customer service that treats everyone equally important. 

In my opinion all Zu speakers sound different and the choice should be based on the kind of room and listening. I bought the Omen Def Mk1b after having auditioned almost all their models. My favorite model was the Soul Supreme; I found them to be more "musical". I ended up buying the Omen Defs because it was a huge deal (nearly half price) and I'm very happy with them. This model is not as refined as the Souls, but can surely rock the house! 
As for amplification, any good quality low powered amplifier will do. I like the chinese tube amplifiers with Zu speakers. Line Magnetic, Cayin and Opera Consonance are great (I'm driving them with a Cayin Mt45 Mk2)!

I have Superfly and I have the Defheads (sealed top half of Definition).  I haven't heard Omen Def, but my Defheads are kinda like the Omen Def with a sealed cabinet and better cabinet build plus the Radian tweeter.  Let me tell you that Radian tweeter makes a difference, especially if you listen to a lot of digital.  I like my Defheads better, but the Superfly are no slouch.  I've used both tube and First Watt solid state amps.  If you want a big, rich deep sound, then probably go for Omen Def.  If you want a more intimate, focused sound, go for Superfly.  As much as I like my Superflys I have an itch to trade them in and go up the Zu line.

I use one of those tiny 3w Chinese tube amps from amazon with my Defheads and it sounds sublime.  How's that for a cheap integrated?

Zus are very revealing of amps.  I haven't used a vintage Marantz, but I have tried 70's vintage McIntosh solid state and Sansui.  They sounded a bit too warm and veiled for my taste.