"what do you guys think about rifle scopes on crossbows?"
Most rifle scopes are parallax adjusted for 100 yards, less likely to be clear/on at the distances that bows are usually shot.
I started with Excal scopes, because the reticule's aimpoint spacing can be adjusted to match the trajectory of most bows, but am truly impressed with the Hawke crossbow scopes. Much smaller and relativley good optics for the $.