I like my Zing-it and Weaver bags (8, 12, 16). I use my Big Shot for anything over 30 feet or for small openings less than that.
I got a suggestion from somebody at the Wisconsin Tree Climbing comp a year ago or so. He uses a bow release on the Big Shot, and then aims and fires from the shoulder. Incredibly accurate that way. It's cheap, and only took a little modification. Works much easier than the trigger release made for it. The release is rated for 200 pounds.
My release position is easily adjustable to give me the height I'm looking for. I now rarely need more than one shot, even at 60-70 feet. It's crazy accurate. I don't remember the guy's name, but whoever it was: Thanks!