Neither. Try a different brand. I have a mix of gloves from different makes. Some in XL and XXL which are both fine, some XXLs that are too tight. Your mileage will also vary.
Go and try some on in a store, or buy 3-4 pairs online and send the ones you don't like back.
Summer cycling gloves: if I'm between sizes, as in both an L and an XL fit, do I go snugger or looser?