I used to have a SSTack quarter sheet, not sure if was the same blend, but it was an older school one without the cutout for the rider. It did a nice job for the price, but I think I eventually got rid of it because you couldn’t put it on/take it off without taking off the saddle, so not so practical. It looks like they’re a more useful style now.
Currently I have one of the Newmarket Rambos, which I’ve been really pleased with. Nice thick fleece, not too flappy while riding. I’ll use it on cool days for the whole ride if I’m just flatting but I don’t jump with it on. My horse is currently fully clipped, as we’re finishing up our show season this weekend, so I’ve already used it a few times this year. Generally I’ll go with it to warm up/cool out if it’s below 45. I find the quarter sheet much more convenient for actually riding than a full cooler, which is what I’ve got along at the show this weekend, and it’s rather inconvenient to actually warmup with, since you can’t really do more than walk, but is much more useful for tossing over the horse/rider between rounds, or walking to the ring.