At first I thought "hey, since Im going to be doing MMA, Ill get Thai gloves, they should be better than regular boxing gloves." I had a pair of twins, fairtex, and even windy. I honestly thought that the twins and fairtex were both better than the windy, but the windy was nice.
Any way, I began using my red fairtex bag gloves for pad and bag work. They worked good.
I was a bit dissatisfied with the boxing class at my academy. I just dont like the format. Its not that it was a bad class or anything like that, its just designed to accomidate a lot of people (IE hobbyists) , instead of guys wanting to really immerse themselves in the art. So I called a pro trainer, great guy. We started doing intense pad work and I was using my fairtex bag gloves. At the end of the session my right knuckle and hand were aching.
Next session I start using my lovely twins gloves. Right away my hand begins to hurt. So, I switch to my winnings glove. No pain whatsoever. Its beautiful.
If I were you I would stay away from your typical muay thai glove. Traditionally MT guys do not punch very much. It is considered the weakest strike to them, and although the twins and fairtex gloves have an inherent quality to them, muay thai gloves dont seem to protect your hand as well as traditional boxing gloves.
Okay, lets not forget that sparring is to learn....not to damage your sparring partner, making him more likely to hurt you or not want to train with you. That being said, you'll want 16 oz gloves. I say for sparring make it a lace up glove. Better wrist support, snugger fit, feels better etc... If you do a lot of drills with glove swapping, like ground and pound drills where guy on top uses full size boxing gloves and attempts to beat guy on bottom, and guy on bottom uses mma gloves and tries to improve position or submit guy on top, then you might be better served to use a velcro securing type glove for convienience, not performance.
My first choice for you would be winning, but thats double your budget.
My second choice would be grant pro training gloves. Known to also be easy on training partners.
Now, personally I will be using 16 oz Cleto Reyes gloves for sparring. These are known as a punchers glove, so not so easy on partners, but Im a 135 pounder, so I figure my training partners will be fine w/ me using a 16 oz glove, reyes or not. I can recommend reyes quality wise, but not so much for damaging your partner.
My other "second" choice would be a product I dont have experience with but have much faith in, are the ultimate classic training gloves. They arent as flashy as some of the other gloves, but I have a feeling that these gloves are just as good quality as the grants or cletos, not to mention they are a bit cheaper, and have a one year warranty. I have a feeling these gloves are made by legacy boxing of New York.
Honorable mentions are fairtex sparring gloves, which seem to be specifically designed for sparring(hence them being called "sparring gloves")
BGV5 - Super Sparring Gloves - Locked Thumb
BGL3 - Pro Sparring Gloves - "Locked Thumb" Design
Fairtex Safety Training Gloves
Winning Products
Grant Professional Training Gloves at Ringside.com
Ultimate Training Gloves - Lace Cuff at Ringside.com
Cleto Reyes Training Gloves at Ringside.com
Fairtex New Zealand - Be Inspired