Got the Barnet Recruit but the scope is a little busy for what I wanted to have on there for my son. I think a single dot scope is the answer since he is only 6, but would love to hear your input?
If you don't have the need for the ballistic reticle in the scope then just about any descent rifle scope will work just fine. Remember you are not going to be dealing with recoil or range as with a gun so IMO I wouldn't drop a lot of $ on one. Another option could be a red dot but you will not have the magnification.
I would get a little 4x scope like you use on an air rifle. You have to be careful of the "snap" of the crossbow, not sure what it will do to a regular scope.
I didn't like the dots either so I just bought a Tru Glo crossbow scope. It is nice and bright and easy to use.