BAT VK 600se vs Electrocompaniet Nemo

I haven't heard the Nemo, but the BAT is a very solid choice. Wilson is pretty efficient and if you're not careful with component selection, its easy to get some hiss, or similar type of noise. Its very unlikely you'll have any problems with the BAT, and it sounds great. Something like an Ayre V-5 would also be an excellent choice, as well as something from Pass.

@ 600 wpc into 8 ohms & 1.2 khz into 4 ohms - The Nemo's will drive any speaker ever built!
I had a pair for 2 years & loved them to death as they had a tube (warm) sound to them, but being solid state they require no biasing or changing costly tubes.
Another great choice would be the Goldmund 28.4

Thanks for the feedback! Paladin did you ever feel like the Nemo's "needed" tubes in the chain? What preamp were you using when you had them?