I love my EasyBoot gloves, and I have never had trouble with them coming off through mud, at speed, or in brush. However, with the gloves, you are supposed to trim some yourself in between farrier visits to maintain the good fit, and I have watched people struggle with them. Have you maybe considered the EasyBoot trail or backcountry model? These fit a little better and stay on better due to the gaiter. Definitely get the fit kit if you're going the glove or backcountry route. I used to hate the classic EasyBoots, btw. They had these metal teeth that bit into the hoof and sometimes did damage, and they were impossible to get off. I think you'd hate them unless they've changed significantly.
I have also used Cavallos and Old Macs, which each also have their pros and cons. At the high end, I'm lusting after a new pair of Renegades, which promise to be more durable and to stay on better. They also come in super cool colors. :)
I've never thought the cost of boots was that bad, but I paid $110 for my pair of gloves, and I've regularly paid $80 for the farrier to shoe a horse. The gloves lasted through way more than one shoeing cycle, so IMO, they're worth the money. The classic EasyBoot has been around a while, and lots of people decide they hate it, so you could probably find some used ones pretty cheap that aren't worn, out, but otherwise I can't think of any that run less than $100 a pair. Sorry. :(
Tug on anything at all and you'll find it connected to everything else in the universe.~John Muir