I learned my lesson from buying my first wakeboards. My first wake deck was an out dated Connely that was shaped like a small surfboard, that thing was a tank. Took me forever to get it up on the water. My second one was a cheap Hydroslide true twin, this one was a hell of a lot easier to get up on plane, but still sucked to ride. So when I decided to plunk down some real money for a set up, I started doing a lot of research, and asking questions on forums. I ended up with a Hyperlite Premier, loved that board rode the same shape for about 6 years. 3 years ago I switched to a Murray pro model, felt like I had to learn to ride alll over again, very unforgiving, and very fast.
When I moved from rentals to my first snowboard, I did a ton of research, and landed here. I ended up with a K2 Brigade 163w that I still ride 4 years later. It's classified as a intermediate all-mountain board, works perfect for me. This year I did pick up a Nitro Target 157w because I wanted something a little more playful, spent Fri. trying to get used to the shorter deck. It's still a kind of stiff all-mountain deck, but with it being shorter and my weight (230) it flexes good, I can butter the shit out of it.
I guess my main point is, when buying a first deck, do some research, don't just plunk down a shit load of cash because you think more expensive is better. Try to find reviews of a couple different models that fit what style of riding you want to progress in. If I would have jumped from beginner/rental right to pro level boards in either sport I think things would be way different in the way I progressed.