After several weeks of research, I finally pulled the trigger on a Domino XL with a CT36 dust extractor. Realistically, the 500 would have worked for the vast majority of my projects, but there are a few that the extra size would be useful, and with the shims and bit adapter from Seneca Woodworking, I figured I would have the best of both worlds. Additionally, several people on other forums had mentioned that they preferred the XL over the 500. I figured if I was as happy with it as the others, then is had just saved myself $900 (by not having to buy both)!
My first impression was that it was pretty heavy. After using it for several test cuts, I decided that it was balanced well enough that the weight really wasn't noticeable. It only took a few test cuts before I was able to make perfectly fitting joints right where I wanted them. My one quibble with using the Seneca shims (I as using the shim for 3/4" most of the weekend) was that the shim raises the guide in the window on the fence enough that it takes a few extra seconds to be sure things are aligned properly.
One of the joints I assembled needed a 1/4" offset making a lopsided T rather than an L. With the shim installed, the clearance below the fence was almost exactly 1", so it was easy to use a 1-2-3 block and a 1-4" spacer to set the fence to the exact offset I needed.
So far, I am quite pleased with my purchase. I expect to be putting it to a lot of use over the next several months.
Lee