Big difference in Vaginas.
I dated a gal in college that had a corridor between her legs. I'm not huge but I'm not small. I got lost in there.
My current girlfriend is extremely tight, and not very long. She thinks I'm WAY too big and mechanically, it's not good sex. A breakup is imminent, even though she gives great head. Sometimes you just need some pussy as a straight guy, and when mechanically it's very difficult, you need to move on.
So yes, there is definitely a difference in Vagina size, texture, feel, muscle control, etc. Some vaginas feel better if you stay near the opening, some feel better when you plunge balls deep, and some feel great labia to cervex.
When you find a Vagina that is perfect for your penis, you know it. Perfect fits are amazing.