There is probably 50 threads on this topic, so I would recommend a quick search and you will have more than enough info to get started.
That said, I don't think the rocker has a quick release/tow setup, which you (and your friends) will want as you get better and start running harder stuff. It will be a good pfd to start with, but you might as well buy a Type 5 and never need to upgrade.
I like the Astral greenjacket. Good rescue features, and some nice padding around your core should you end up splatting on a rock. There are also several pockets to store a pin kit, first aid, sunglasses, etc.
Life is either a daring adventure or nothing. - Helen Keller