it doesnt matter if you have fins or not if you do lip tricks because they will be out of the water and only the middle of the board will be touching the wake.
my brother has a catalyst. its a good board, but i certainly wouldnt buy one for myself. its an easy board to find at shops since its made by hyperlite, and you can usually find places to demo it too. if you are 150ish you can ride the 107. the catalyst ONLY comes as a foam top, which i personally dont like. its also very light and i dont think it feels as solid on the water.
butter boards- i believe it only comes as a 42 inch. i actually really liked it. its kinda like a happy medium between the catalyst and the cassette. it has the foam like the hyperlite and its compression molded, but it has the weight of a cassette, which i love.
cassette concave- a good friend of mine has a 41 inch version. its incredible. after riding my bro's catalyst, the cassette feels like an F'in cadillac. its much heaver, has grip tape, and is just an all around great board.
integrity- the boards are currently in production and you can order them at www.integrity-wake.com
they are composite boards, but not compression molded like the butter board and catalyst. they will come with grip tape and a new graphic for every 50 boards produced. there is flex in the ends of the board to help you ollie, and they are sweet on lip tricks. they are about the weight of a cassette. they come in a 41 only.
whatever you get i would stick with a concave. you get much better feel for the board and much better control.
hope this helps...