I have the alpha fins because they were highly recommended from the swim coach that I am using. I have only used them a few times so far but they feel great. I wish I could swim a fast as I do with the fins on all the time.
I use the Zoomers Z2 and they suit me fine. They are a little stiff and occasionally cause blisters. After trying some Alpha Zura's (Aqua Sphere Alpha Fin), I'd probably buy those instead.