I actually own both LTWOO and Wheeltop on two different bikes. A few notes
- The Wheeltop officially supports 51 not 52. I suspect that 52 would work but, then again there may be a reason they topped it there
- LTWOO has a new RD that DOES work well up to at least 50t. I got it on warranty (charging problems) and they asked if it was ok to send the long cage version (8-9mm longer as it turns out) instead. Heck yeah, I said since I was using the 50t already out of spec. They did not provide any documentation on the new version and I find NOTHING online and there are no markings. So... But it seems clear that there is a new version working into the system and that it supports bigger cassettes. How big? Is it a configuration option or a replacement version? Did anything else change? I don't know. It works well. Better than the original it seems to me.
- The LTWOO strange caliper adapter thing is not great. But seems to work with most. Wheeltop calipers just flat mount with no issue
- Braking feel is kind of a wash. My opinion is problematic because I couldn't use the LTWOO calipers on the first install because of having a post mount bike (I had been led to believe I could just use different adapters. No). So I just used some Shimano calipers which worked great but not exactly stock. When I swapped in the Wheeltop system, I left the Shimano calipers (easier to just couple in than re-thread the hoses) and that worked fine too. When I re-used the LTWOO again on the second bike, I ended up using the Wheeltop calipers

because they mounted without adapters. So.... It all works. Braking feel and effectiveness is good on both mutt systems. The pads that come with the Wheeltop are bad if you're heavy and/or ride mountains. They feel good riding in unchallenging areas but they melt way too easily on a long descent. I have resin pads on another bike that works fine and these did not. I put metallics in there and it's good now.