I have the jaguar leathers with the comfort buckles. They are incredibly comfortable and have lasted well BUT that has been on my dressage saddle. I have used them for jumping recently (say 10 times) and the holes have started to stretch already, I thought they were supposed to be non-stretch so I am a bit disappointed.
I have a pair of lemetex ones that I have had a long time and I dont think they have stretched, but I did get them restitched at the buckle recently (cost a grand total of £4).