I have both an XPA-2 and an XPA-200. I have used each of them to drive my Gallo Reference 3.1 speakers.
The XPA-200 is currently driving the 2nd voice coil of my speakers which allows my speakers to have nearly sub woofer capabilities. It does a fine job and I now have the bass I have always wanted; tight, well defined and deep. It isn't quite as forceful as I might like, but it is not the fault of the amplifier.
I have also tried switching the XPA-200 and XPA-2 to allow the XPA-200 to drive the complete frequency range.
It seems to be a little less detailed than the XPA-2 and maybe just a tiny bit smoother. Of course, it isn't as dynamic as the XPA-2 because of only being 150 watts vs 300 watts.
With the price difference compared to the XPA-2, the XPA-200 is a terrific bargain.
With that in mind, if I had heard both before buying (I got the XPA-2 first), I'm not sure how it would have gone. I might have wound up with a pair of XPA-200s.