I'd have to say I prefer rolling in a gi a lot more fun. When I first started MMA i preferred no-gi grappling like a lot of beginners since I found the different grips frustrating, but after being persuaded by my head coach to take up gi as well, I just fell in love with it.
I really do believe that while no-gi is an integral part of grappling, you never really learn the beauty of BJJ until you learn in a gi. A lot of my sweeps, submissions and set ups come from a high inside collar grip and gripping the cuffs on either the trousers or the sleeves, and lets not forget those sneaky gi chokes!
And one of the most important bits i found in training in a gi is that it makes your defense so much tighter. Since there's so much friction in a gi, you can't just slip out like you can when youre rolling no-gi, so you have to have your timing and positioning on point.
while i seem to advocate gi rolling, i really do have fun in both and I'd encourage anyone to have healthy dose of both like i do with my own students.
EK BJJ/ Team Bloodline