I hand circumference was on the border line between small and medium so I went with the medium. They are tight. I would suggest that if you size up for these gloves if your measurements are not close to the low range. The gloves are very comfortable and provide good padding.
Gloves are like saddles and shoes: There is no "best," only "best-for-you." These gloves deliver for my large, bony hands--very plush. Giro sizing is random, and constantly changing--I have worn Xl and XXL in Monaco, I got these in M because reviews said they ran large. Brand new, they were skinsuit-tight, but they stretched to a comfortable, but snug, fit. I could easily size up, but I think the padding would bunch at the base. I think these are an excellent choice if you need some extra cush, and the fit suits you.
High end glove and fit is perfect in large size. This glove really molds to your hand with long lasting comfort. Fit is true to size and probably the best glove I have worn in quite some time.
Comfortable padding, great fit )XL). Holds up very well to daily washes. The stitching on the right index finger is coming loose but that doesn't seem unreasonable wear after about 2000 miles.
I ride 2-3 times per week averaging 25-50 miles per ride. Thought I'd give these a try and I'm not disappointed. I typically experience numbness in my hand and the first time I wore them I realized I was well into my ride and I hadn't gone numb! I can't say they've reduced the tingling entirely, but they've reduced it significantly. I have at least 10 pairs of gloves from several different brands and these are my most comfortable, I'll buy another pair.
I just used these on a 80+ mile back packing trip. They have padding/ feel nice. However the best feature are the two pull tabs on the middle two fingers. I found myself utilizing the tabs to easily adjust the gloves on the fly. I have others without this feature that just get all bunched up and uncomfortable/harder to adjust on the fly.
You don't really notice how little your hands go numb until you think about it after a few rides. Much better than other gloves I've tried and I've tried a lot.