Spectron III or MF Superchargers + tube amp?

I own a Spectron Musician III (not the SE mk ii version) and it's driving a pair of MBL 121 monitors. Tube preamp is Supratek Syrah. I'm enjoying the sound pretty much, but am now wondering on which of two options to pursue - either to upgrade my Spectron to latest version, or to sell it and get a tube amp helped by a pair of the Musical Fidelity 550 Superchargers. The MFs may give me all the power I need, but also that tube sound which I typically like.

Does anyone have experience comparing the latest Spectron to MF Superchargers + tube amp. I do miss tubes a bit, but maybe the Spectron upgrade would make me not miss tubes any more.

Anyways, any advice would be most welcome. Thanks!
The MF Superchargers plus tube!! Why?? Because I don't know of anyone else who has done it, and I want to know how it sounds because it intrigues me with my set up. Good luck!!!

In the current isssue of Stereophile (Dec 2008) there is follow up of supercharcher MF 550 and reviewer did not liked it because this amplifier clearly impose its own sonic signature on the system sound overdhadowing sound from small amp. He found it to be overly bright both as supercharher and as the amp by itself.

John Atkinson also have the same conclusion: too lean and too bright
John did review of new MF Supercharger 750 ($10k) as stand alone amp and he likes it but no more (sort of "OK")

All The Best