I've used plenty of Timneys (510 and CE), TT, Jewel, Shilen, etc., and my preference is the TT Special. I had one issue with sear engagement that ended up being caused by incorrect bolt timing on a M700, and TT worked with me and went way above and beyond to help me get the issue resolved, including custom making a trigger with altered sear engagement (free of charge) to keep me going until I could get the bolt timing fixed.
Both my competition rifles have TT Specials, and both have thousands of rounds on them with nary a hiccup nor a cleaning.
