Maybe you guys have heard of Karate master Barry Stephen. Very accomplished in various kickboxing leagues and been around the scene for a very long time. He started this line of gear and Bas Rutten endorses them. The guy who started my university's kickboxing club where I teach and train at is one of his star students and hooked me up with a very good deal with their gear.
Anyways, these are hands down the best sub 100 dollar gloves I've ever used.
Thunder Cardio Gloves
Don't let the name fool you. These are supposed to be their bag gloves and I can't imagine how nice their pro series gloves are going to be. The leather feels very plush and soft. The padding is VERY nice. You will know the first moment you run your fingers over it. Completely suitable for sparring. And it keeps its form for a long time also. Mine were 16 oz.
I sparred with them every week and sometimes used them on the bags. I used them for a good 6-7 months before they got stolen. The last time I used them (gawd I miss 'em) they felt like they were 2 weeks old. The only gripes I have about them are that the velcro is pretty strong and if you end up rubbing them against your partner it'll leave a nice rash.
I really can't believe these guys are under 50 bucks. Go get 'em!