We really like it! The hunter Al is in charge of is on it and it keeps him ticking along very nicely (he's 18, and about 17.3hh, and has hunted hard all his life so he needs some help!). Reg is on Vetrofen, which has also been fantastic. You can really really tell the difference in both horses when they're off the stuff- Cortaflex made virtually no difference to them though.
Also just found Premier Flex HA online and also like the sound of the reviews.
I use a supplement as my big young mare has bench knees and I'm trying to keep her as sound as possible for as long as I can. So far, so good. Want to keep her that way!
It's just hard deciding which product to opt for as a long term prophylactic.