you can not go wrong with any of the Sundown products. I personally would not pick audison over sundown. I would be very suprised if you could hear any difference at all.
The PDX amps are Class D lol... full range class D... can never sound as good as an AB amp IMHO, but everyone has an opinion and I am sure plenty would argue that with me, I will ignore it thank you.
SAX-100.2 = standard Class AB design and a lot more than 100 watts x 2....
Only ways to get a "warm" sound are with high even order distortion, poor frequency response (exaggerated low end, roll off on the top end or both) or single digit damping factor. All other than the last are not what I would consider high fidelity. The last is just a matter of preference.
The Sundowns do not have distortion in the realm of audibility. The frequency response is flat all the way through the audible range. Damping is more than adequate.
If you are looking for the accurate sound of a high quality amp like an Audison the 100.2 will do it. An Audison dealer reviewed the SAX-100.4 and compared it favorably to the Audison... and he doesn't even sell Sundown Audio (although, he did buy that 100.4):