Here's my experience with a set of TPS alloy rings...
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2270336&page=1TPS customer service leaves a lot to be desired. For one thing, its next to impossible to actually get in touch with anyone at the company. Emails go undelivered or not responded to, and reaching someone on the phone is an exercise in futility. If, and that's a big "if", you do reach someone on the phone, it will be the sweet older lady who has no clue what is going on, can't find anything out, but will gladly forward your information to one of the techs.
They did eventually replace the rings, but it took a while. Truthfully, I would buy another set, as their steel rings are top notch. I believe its possible the failure I had was a fluke, and I can accept that, but dealing with customer service was a PITA!