Bunny boots are great, but not great to ride in. They are just too large and heavy. I have a pair to ice fish in and they are just too bulky to fit nice in the foot wells. But you'd never, ever be cold in them. And there is no lining, they are just molded rubber, so if you get them wet somehow you can just wipe them dry and keep going, unlike boots that need a liner to dry out. They are also $39 most places, so it's not like it's a big investment to try them.
I have ridden in Sorels for years and have liked them, but they are not great for aggressive riding. I get about 3 years before the rubber starts cracking/tearing and are no longer waterproof. But they are light and cheap, comfortable and warm. $99 for 3 years isn't bad. I'm actually on the hunt for a new pair of riding boots and can't decide myself so I will keep my eye on this thread.