I'm on the other side of the fence... I've ridden in spurs maybe once or twice? I just hate the idea that my horse might become dependant on them, and I wont be able to ride him without them.
I find the idea of a spur stop very strange... lol. I've always learnt that the 'whoa' aids come from your seat and to a degree your hands/voice. Your legs are there to position your horses body, lift their belly, etc... Not to enforce a whoa. I aim for my horse to always move off my leg, not into it... Hmmm. So not sure how a spur stop would work!!