Of these two choices, I would choose the BAT VK-51SE. It has a more powerful presence, with better tonal accuracy and soundstaging. The Synergy IIi is slightly more refined and does have more transparent high's.
FWIW, I am currently using a pair of Jeff Rowland Model 6 monoblock amps, but I prefer them w/o the battery supplies. IMHO, the batteries make the sound smoother, but at the expense of dynamics. I think the Model 6's are smooth enough that I'd rather have the extra dynamics than the extra smoothness. I'm currently using a ARC Ref 3 preamp, which I thought bested my previous reference, the BAT VK-51SE.
Happy hunting,
John
FWIW, I am currently using a pair of Jeff Rowland Model 6 monoblock amps, but I prefer them w/o the battery supplies. IMHO, the batteries make the sound smoother, but at the expense of dynamics. I think the Model 6's are smooth enough that I'd rather have the extra dynamics than the extra smoothness. I'm currently using a ARC Ref 3 preamp, which I thought bested my previous reference, the BAT VK-51SE.
Happy hunting,
John