I have an Ultradot on my 22/45; I got it from Jack Weigand at the same time as the screw-on mount you're considering. It's (the mount, that is--though I like the red-dot too) a nice piece of work, in my humble estimation. Very secure, pretty light. Only beef, if I had to name one, is that it appears to raise the line of sight just a little higher than the solow might (hence the name, I guess); but it's not a beef that bothers me at all, and I didn't like the idea, frankly, of the goo involved with the solow. Folly on my part perhaps. My camera battery tells me it's tired, or I'd post a pic for you; just email me if you want to see it on my 22/45 (it's a 5.5" bull barrel)
CG