I was certified last November, and about a week into the class I decided that I would feel safer and more comfortable in my own gear. And I did, but the trade off was spending boo-koo bucks and not knowing whether or not the sport would work for me. I was a bit stressed on the first dive, not knowing if I would have trouble clearing my ears at depth, or if I would hate the sport, and all the fancy gear I had would be sold for half the price, and some of it (like the customized dry suit) would just be a complete loss.
Lucky for me everything worked out, but I can see how it easily it could of been a big mistake. Before picking the gear, I spent hours researching dive magazines, chat boards, and talking with dozens of dive shops about gear choices. Not being certified, I wasn't able to test any gear and had to make my own decision about things I know little about which was particularly difficult when given conflicting information. I don't think my choices were perfect, but 9 months and 30 dives down the road I am very content with all but my bc selection. My bc works for me, but I believe I can find a better fitting and more flexible setup, so it will probably hit the used listings in the next few months.