Hi James!
Well, the "cube" revision is one step ahead of the "SST2" revision. Try to remember that if something is spectacular-sounding today, it will still be spectacular in ten years. Take your SF amplifier for example, it is still very much sought after. I have a friend in South Africa who swears upon these amplifiers and can't get enough of them even though the brand doesn't really exist any longer.
What I would suggest is for you to borrow a Bryston amplifier, let's say a 4B SST2 or similar, just to experience it with your speakers in your room. If you like it, you will certainly like the newest models even more. If you don't, I doubt you'll find the improvements with the newest models sufficient to suddenly start liking it.
Cheers,
Antun