Both have their pluses and minuses. The tightest I've had (which incidentally was a very chubby girl, so there goes *that* stereotype) left me with sores on the shaft of my cock several times. The loosest I've had was oddly enough the hardest for me to "last" and it also was fun to fist her. While there's nothing quite like breaking through and bottoming a tight pussy, they aren't as comfortable for a nice long fuck.