To be honest, I also bought a board and I have about the same experience as you (in years although). I bought the Burton Clash, with customs and motto boots. I liked riding it so far BUT I only bought it because my budget didn't allowed anything else and I got 10 % of the whole setup, including a travelbag. So, with other words, your budget can keep you down in progressing because you are already more then a beginner and you're buying a beginners board (I did it too, regretting it now, if i knew I earned a little bit more money and went buying a better board).
The Burton boards you're looking at are for beginners, I don't know about the GNU. But I'm sure more experienced people on this forum can help you with picking the board. Also, first look at the boots, then the bindings and then the board, and do it in exactly this order.