I have just switched and started mine on alpha bute which used to be bute x from global herbs. It does not contain devils claw. Too early to see results yet but hasn't noticiably deteriated.
Devils relief by NAF, its got devils claw and MSM , antioxidents etc so its much more than just a painkiller. Good value to compared to the others with similar spec.
The most effective I have found is Bute Free by Gold Label. It contains not noly Devils Claw, but Yucca and MSM. It is also cheaper than many. (that's just a by-the-by bonus)
I feed pure Boswellia Serratia (Its also the main ingredient in the global herbs bute free supplement, cant remember the name!) and find it far more effective than devils claw and its gentler on the stomach.
Tried my mare on numerous types of liquid bute free supplements can't say long term it has made much difference but is useful for little knocks and swellings along with arnica. Someone has just told me that the Devils claw root granules are better long term although of course take longer to get into the system just trying them myself? Also if you soak them in water the night before they will get into the system quicker apparently!
I use no bute on both mine, one for arthritis and the other for stiffness. have to say i see a difference when they are off it. I will never take mine off it, love it!