We had to give our mask to the dive instructor in training then he put it on the other side of the pool. We had to go get it, put it on, then clear it. It was a little intense at first, but you get used to it.
Still need the snorkel when you're diving just in case you need to breath on the surface with your head underwater. The scuba quality ones definitely aren't cheap, but they're very nice.
It's weird moving underwater for so long. You use muscles that you normally don't move because every time you move, you meet resistance. Fins help the propulsion part though, for sure. Let the big muscles do the work.