I went from a QCK Heavy (extra thicc mmmm) mousepad to the extended MM300. I now have all the mouse mat space in the world to play fps games with comfortably low sensitivity and can freely swipe as far as I want without worrying about falling off the edge.
Extended mousemats typically serve two purposes: aesthetics and serious mouse swiping. If you're not too concerned with aesthetics, don't have a huge amount of desk space, and don't swipe your mouse like a madman just to turn a 180, I wouldn't bother with one. I would personally weigh speed vs control and material comfort over size, especially when mouse mats only seem to be getting bigger and bigger these days.