I have the Tekno mount and Vantage carbon fiber wing. I really like the mount, it has a lot of different positions for the wing. I haven't seen the Jconcepts in person so I can't say.
The only draw back to the Tekno mount is if you still use he stock body. You have to cut out a lot of the back end of the body. If you run like a Crowd Pleaser body that doesn't cover the rear end of the truck you wouldn't have to cut it as much. You also can't adjust the rear height of the body with the Tekno mount.