Dude, I love the set up, great choices on speaker/amp combo.
I also have a Drobo/drobshare (to AppleTV) and I love my digital setup. I went through many DAC's including the ones you mentioned before I finally picked the one I kept, which is a Bryston BDA-1. I think the Berkeley Alpha was better all around looking back, but I think the Bryston sounded warmer with my gear, so I got that one instead. Next I liked the MHDT Labs Havana the best, and it was much less than either of those. It's incredibly musical, and as much as I listen to digital, I probably should have stuck with that one. Not as detailed or extended (espcially compared to the Berkeley) but just sounded great!
Good luck.