Vienna Acoustics Mozart or B&W 804

Well it looks like the upgrade bug has hit me. I currently own a pair of Vienna Acoustics Bach. Overall I am very pleased with them. Not much to complain but... the audiobug has bit and I am thinking about moving up.

My two choices are the Vienna Acoustics Mozart or the B&W Nautilus 804.

Any opinions on these two? I can get the 804 close to the price of the Mozart. These are the largest speakers that would fit my room dimensions. My current setup is the following.

Congrad Johnson Sonographe SA 400
Conrad Johnson PV 10A
Yamaha CDC 575.

Has anyone upgraded from the Bach to the Mozart? Is it big jump in the overall sound quality? I would appreciate any opinions.

thanks
cmach

PS