I have several high end mounts but just bought a UTG Accu-Sync for a project I'm working on. I've only had it for a few months but so far so good. They can be had for under $40 on Amazon and they're actually pretty light though they don't look it. They come in several colors and a couple of heights (which they call 'off set'. There are a couple of Youtube videos out there if you're interested.
https://www.leapers.com/index.php?act=li...%20SYSTEMS
https://www.leapers.com/index.php?act=li...%20SYSTEMS