So in pro practice, we spar with MMA gloves. (with more padding than fight ones). But I've noticed that in the general classes, the beginners often put on MMA gloves, along with shinguards (no headgear) to do kickboxing sparring.
Now. It's true that people are encouraged to spar lightly -it's the end-of-the-class sparring. However, I believe that beginners should use bigger gloves- AT LEAST bag gloves- if they do kickboxing. I wouldn't want to get clocked by a beginner going nuts with MMA gloves, if he or she hasn't learned control yet. It's dangerous, right?
On the other hand, big gloves get in the way and block punches more easily, so it's easy to get sloppy with blocking. I've heard the opinion from a teacher that beginners using MMA gloves to spar lightly is good to teach them blocking.
What do you guys think? 
If everybody in the class has good self control and doesn't escalate every time they get hit, the MMA gloves are probably great. Then again that's a little less likely than all of them riding unicorns to the gym.
Even in pro sparring, we dont use mma gloves.
We use mma gloves for grappling or VERY light sparring (timming).
All our amateur always use boxing gloves, 'cause here in Quebec, we use 10 oz boxing gloves for amy fights. 
Stand up sparring use big gloves but move head more than you need to.
I always use big gloves sparring stand up
I basically quit going to a gym that was very close to my house because they did they same thing there. They didn't enforce any rules when it came to sparring gear and there were to many fools in there that must have had nothing to lose.
We use MMA gloves for advanced students/fighters. I think smaller gloves reduce complacency. People tend to defend themselves much better when they run the risk of getting cracked by a MMA glove vice a boxing glove.
AwHood -We use MMA gloves for advanced students/fighters. I think smaller gloves reduce complacency. People tend to defend themselves much better when they run the risk of getting cracked by a MMA glove vice a boxing glove.
Seriously?? You spar 80-100% with mma gloves?? What about cut and concussion?
Thanks for the replies, guys. You basically confirmed my instincts. p_p;
We always used 16oz., well most of us at my school.
I also use the boxing gloves to practice with positional drills. Adding strikes to a grappling session changes your normal strategies. I’ll have a guy top mounted with boxing gloves and the guy on the bottom wearing MMA fight gloves. Guy on bottom will not strike and will focus on defense and getting out of the bad position. This drill especially helps with guys who like to make a lot of space as they get clobbered real fast.
When I take boxing we always use boxing gloves. Sometimes we do san shou type sparring (kickboxing + takedowns) with boxing gloves.
We always like to MMA sparr with the extra padded MMA gloves. When this happens hand striking is like 60-70% TOPS kicks + grappling are full go. Believe it or not the speed, timing,and defending is completely different with mma gloves.
We favour the larger gloves for kickboxing sparring, accidental concusions are not something to snear at.
Protect yourself at all times, but the gloves help too.
At least 10 oz for me when sparring boxing. Also, be careful that your gym doesn't mix bag gloves with sparring gloves. Mine did, and I got a cracked process bone (between eye and ear) and concussion for my troubles.
At Alan Belcher MMA, we use puffies (7 oz MMA gloves) for MMA sparring, and go real light. No headgear because its just about touching and timing. All amateurs and pros and everyone stays in control. Morr about mixing it up so there is a ton of grappling. Twice a week its full headgear, shinguards, and big gloves, and we still go 40% or so to work technique and proper form, good habits, etc. Once a week its big gloves, headgear or no, and people are going hard to simulate a fight. Even then its not 100% at all. I think its a good setup, you get good looks, and people are never trying to hurt each other. I hate that tough guy shit.
There are pros and cons to each. Safety is the obvious pro for boxing gloves. Technique is the big pro for MMA style gloves. Something that I think is overlooked, is that if more heavily padded MMA style gloves were the norm, we'd see a sharp decrease in eye pokes.