ThemeForest has a pretty bad rap in the WordPress world. It's incredibly popular for anyone who doesn't know anything about HTML & CSS because of the cheap prices and huge selection. There is of course a catch – the cheap prices reflect the quality of some of these themes. While the screenshots look nice the code infrastructure that you pay for is very poorly built. If you have any aspirations to use one of these themes in anyway other than the author intended you'll likely run into a whole bunch of issues. I recently modified a ThemeForest theme (which I'm not going to name) for a friend and here are just some of the issues I ran into.