I’m another who dislikes fiber footing. Historically, my horses haven’t held up well through the weeks at Tbird, Thermal, etc…or at least not as well as they do when jumping on “natural” (e.g. sand, dirt, grass) footings. I find that they get much more body sore than they do jumping on plain old sand. And I blame the under-watered GGT hunter ring at Thermal for the coffin bone bruise that took one of my horses out for a year and a half. I think it gets way too hard in hot climates when under-watered (to be fair to the show, we were jumping 1.30m fences in a little hunter schooling ring, and we knew they weren’t watering/dragging like they were the show rings, so it’s absolutely my fault for making a poor decision…I just didn’t think it was that poor of a decision).
I will say that the first year Tbird did GGT in the big (but not GP) jumper ring, it felt like my horses were jumping on clouds. LOVED it that year. But I haven’t had that same feeling since. And I notice that by the 3rd or 4th day of the show my horses don’t feel as good as they do if we’re jumping on the grass.
Like Mac123, my favorite footing is sand + rubber. But there are so many variables with all of the above (type of sand especially, whether you’re talking rubber or GGT or another fiber), that it’s tough to say definitively what’s best.