The offer I obtained for this X-wing SL R-200 is very attractive, it's ~US$800. I have another option which is a pair of Stratos Mono for $1,100.
I know it may be a stupid question to ask, which one would you choose? There is no way I can arrange an audition of both amps in the same system.
I know just about everyone else here is more qualified to answer your question than I but over the past six months I have spent a lot of time watching used Odyssey gear go up for sale and have learned quite a bit. Plus, I have acquired a pair of Stratos monos in Khartago cases and a Tempest Extreme to drive my B&W CDM 9nt's and have been enjoying them immensely.
So, while I have no idea which of the two amps that you listed is better, I would suggest a hard look at the monos. For the price you listed and if they are clean, 3 to 4 years old with redboards, offered by the original owner and without any known problems, then I wouldn't pass them up.
I suppose the best advice would be for you to call Klaus for not only would he know both these amps better than anyone, but he could give you specific advice regarding what would be best for your particular use. And... I've been told that he does sell not only his new offerings at bargain prices but also has B stock or refurbished gear at very reasonable prices as well.
While I have absolutely no regret about my purchases, I am a little ashamed that I didn't give Klaus first chance at a sale and I would suggest that you not make that same mistake.