200w/ch stereo amps: best 1 for under 2000 used?

Looking to get 2 stereo amps of around 200 watts/channel, and under $2000 used. That puts several amps into contention:
Krell KAV-250a
Byrston 4B ST
Jeff Rowland?
are there any tube amps to consider in that price and power range?

The amp will be paired with a Sonic Frontiers Line 3 preamp, and drive dynamic speakers that are not too efficient (87 db) with a 6 ohm nomial (4 ohm minimum) impedance, in a fairly large room (16ft x 45 ft x 9 ft)

I'd like to know what people think? I've been generally thinking of the KAV-250a and Bryston, but have seen other amps come up that seem interesting a potentially good value? What do think would be a good buy in the price range and in the application?
Hey Redkiwi,
great post, and very well stated. I was not discounting PRAT in any way, only taking a shot at some of our friends across the pond who sometimes lose sight of other musical values in their pursuit of PRAT (I won't naim names) (oops). But you're absolutely right, it's one of the most important aspects of reproduction, and one that many pieces of otherwise exceptional gear can fail miserably at.
Hi Karls

I agree totally - I have never liked either Naim or Linn stuff much. Shame they make this PRAT issue such a dogmatic one, and therefore less well considered in audiphile writings than it should be.
Redkiwi, your statement about car audio vs the typical hi end audio blunders, is waaaay true