Manley Neo-Classic500 vs VTL MB450

Anyone compare these two amps side by side? Or has anyone given a good listen to the Manley alone? Ive read a lot about the Neo-Classic 250 but I have not heard anything about the 500. Does the 500 use el 34s or 6550s? Any input would be much appreciated as I am about to purchase new amps and I know I definately want to go with big tubes.

Here's the site to the amp in question:
What are your speakers, by the way? Do you absolutely need 500 watts? My opinion is based on having and living with VTL 750 and the 250's here for some time. FWIW the inside scoop is that the EL34'd Manley will give more midrange liquidity and inner detailing/beauty than any 6550 design. It may not be completely neutral but is stunningly beautiful and lush without being fat or slow. Piano has never sounded more real than the 250's on WattPup7's. Bass was slightly deficient in triode, but not a big deal as you can switch to linear for more juice. An embedded Manley person once told me that they'd take the 250 over the 500 anyday FWIW.

Speakers are Vandy 2CE Sigs soon to be 3A sigs and room is 14'x 35'x 8'tall with speakers on 14' wall. I am also running (2) 2WQ subs. Current amps are VTL MB 125s. Even with the subs I just cant seem to get much mid bass. Tried speakers in all different locations.
Unfortunately I do need 500 watts but I really fell in love with the EL34'd Manley 250s. I don't have the opportunity to hear the Neo-Classic 500s to do a comparison. I do know that the 250s could not really 'drive' my speakers with authority, especially the bottom end.