Markmc, I own the latest version of the SA250 and use it to drive Thiel 3.6 in one of my systems. Frankly I prefer valves to either the SA250 of the Classe CA400. But if you have speakers that demand solid state - as the Thiels tend to, and I suspect the Apogees you have, then either of these amps is going to give you all the drive you are likely to need. I cannot comment on the DR9 as I have not tried it in any of my systems. As to the comparison between CA400 and SA250, I definitely prefer the SA250. I am ultra-fussy about mid-range timbre, tonality and texture and all solid state amps I have heard have some kind of problem here. I have described the CA400 as having a dry wiriness in the midband, and it is only in a very narrow frequency band, but for me it takes away the musicality from voices and mid-range instruments - you just cannot quite focus on the natural tones of the singer as well as I would like. If you play mainly electronic music and rock the CA400 does a pretty good job, but for naturally recorded voices and acoustic instruments the mid-range problem I refer to is too intrusive - for me and in my system. The SA250 is not immune to the problems of solid state amplification either. The SA250 has an artificial sweetening effect on the lower and middle mid-range (which is useful with the Thiels I must admit), but then quickly crosses over to a slightly mechanical and electronic upper midrange. Neither effect is large, but the steepness of the change in character is what draws attention to it. The other issue to look out for is that the SA250 has a bit more treble energy than the CA400, which may be good and then again it may not - it depends on your system. I hope this helps.