VAC 300.1 compared to VTL 450 Mk II or similar

I cannot be a leader here. The Vac 300.1 was much better than my previous model VTL 750 Ref's. I used the VTL single ended, which may be against the majority as far as getting the best out of the VTL. It was not close though. The VTL was just not a good match with my speaker. Not to say that this would hold true with all speakers. I would imagine the VTL may be better with Wilson's , Avalon, or certainly Maggies. So yes, the answer IMO is system compatibility, and the preamp/amp synergy important also.
Good luck Tim.

I can't imagine the VTl sounding better then the 300.1 on any speaker, well maybe the maggies since they practically need nuclear power.

With the older wilsons the VTL's might work better but with the newer tamed Wilsons the 300.1 would bring them to life.

That vintage of VTL's had such mediocre output transformers that they are often helpless in the face of tough loads, notwithstanding their wattage ratings, and VTL was obliged to offer a "Signature" transformer upgrade. The Siegfried vintages, however, are truly fine tube amps, with quality output transformers and beefy power supplies.