I have a couple of the new ones with the single strap and while they're nice, they don't have removable poppets. That bothers me. I've read that you can remove them and insert the universal poppets, which is fine, but I question the abilities of the universals.
I also had issues with posts getting stuck and had to send a couple kegs back for replacements.
Having said that, I'd still buy new. I just make sure to put in the comments on the order to make sure the posts can be removed before shipping.
I have 3 used kegs that I got from Midwest about 3 or 4 years ago that were $30 a piece. The prices have doubled in the last 2 or 3 years. It's crazy.
Might as well buy new.