Wow, a lot of info that is out there about this and that, and a lot of research to do. First, where are you located? What is close to you that might have some crossbows that you can shoot? Me, I looked at several and went with the Excalibur Matrix, but it was a little more than your 750 budget. But with this said, you have several options in the Excalibur series. Best thing about them, you don't have to have a press or take it to the shop to get a string change
I would shoot several first, maybe visit some crossbow specific sites, www.crossbownation.com
is one of them. There are several options to buy them at some online sites as well, and it can be a lot less expensive to do so.
Hope some of this might help....