I have tended to stay away from scopes (by "scopes" I mean telescopes - which by definition magnify) on my crossbows - largely due to the short ranges and the general PITA scopes can be in less than optimal weather conditions.
For a while, I've used the peeps that came with my bows, but I'm one of those people who can't use peeps well.
On my Horton, I picked up a $20 (CDN) airgun red dot, and found it reliable, and much better than the peeps were for me. However, the adjustments weren't a fine as I'd like (and I'm not very particular), and I had an old Weaver Quick Point ambient light red dot sitting in my loading room. I bought a standard 7/8" base for my bow, and mounted the Weaver. I guess the dot must be about 15 minutes, but at archery ranges its not a problem, and its great not having to adjust brightness and monitor batteries.
What I do is establish a zero that's a little short of the range I establish as being my maximum - say 30 yds with a 35 yd maximum shot. I then walk up and back establishing the actual points of impact of my bolts at the various ranges with a centre hold. With the Horton, I was a little low out to about 15 yds, a maximum of 4" high between there and 30 yds, and 4 or 5 inches low at 35 yds. With these factors established, I could "hold-right-on" anywhere within my established range. A 9" difference in impact point height will keep a bolt in the boiler works of any deer or moose (or bear) I want to shoot.
So, that's a long way of saying "I like red dots". :twisted: