<ul><li><a href="http://www.engadgethd.com/2008/05/07/pioneer-introduces-elite-bdp-05fd-bdp-51fd-blu-ray-players/">Clink</a></li></ul>

Partly to do with isolating the transformer from the rest of the circuitry, mostly to make it look like it's better than it probably is (more stuff inside type effect).

found a Musical Fidelity A3.5 integrated amp for $975 on audiogon (retailed for $1700). It's a discountinued "dual mono amp" rated at 150wx2. Decent match for my pair of GS10? Price seems ok. Hit/skip?

Just got an Onkyo A9555 but it can be returned if the MF sounds better....

It's a very capable amp and it won't disappoint, but for a grand I'd want my amp to do more than 'not disappoint'. The main concern I have is the character of a Musical Fidelity A3.5 (I know it well) isn't ideal for the GS10s. MF's sound works better Castle, Ruark or Revolver speakers.

I'd hold out for a Naim Nait 5i (there's been a couple in the last week or so) or an Audio Analog Puccini/SE.
Either of these (or what's in the link) will be compliment your speakers brilliantly.<ul><li><a href="http://cls.audiogon.com/cgi-bin/cls.pl?intatran&amp;1215563211">Or one of these beauties if you can spare a few more shillings</a></li></ul>

since you know the MF very well, exactly how does it differ in character to the Plinius or Naim Nait that makes it not work as well with the GS10?

I see that another good thing about the Plinius is that it has a phono stage built-in.... might even be worth the extra cash assuming the onboard phono stage is decent. And yes, it is a beauty.

a bit metallic and clangy. Not such a big deal on some speakers, but not a good idea with metal dome tweeters.

The Plinius, AA and Naim amps mentioned are very smooth, musical performers and do really well with the music you enjoy.
A Sugden A21a would do really well too, but they don't show up on Audiogon much because once people get hold of them they don't want to part with them.