Just because a keyboard looks cool doesn't mean it will still look as good to you after a long Internet session. A sensible keyboard layout is all important. After that, extra features should be considered a bonus. You can usually handle a keyboard in a shop and get an instant feeling from it. Generally, you pay for what you get with any computer hardware, and the more you pay, the better quality you get.
Internet keyboards are no different.
An important consideration is the ability of the supplied software to reprogram the buttons. You should be able to change this button to run, say, your favourite word processor instead. The real value of Internet buttons on a keyboard is nebulous. Generally, this means a more efficient mode of operation because you don't need to take one hand from the keyboard to navigate the mouse pointer to the button or task you want to do. It can be faster to use the mouse for everything rather than mix and match between keyboard and mouse.