John... USB ports are used for hooking things up the the computer. It's just a matter of convenience that HP has 3 of these on the front panel. So, for example, if you want to hook up your digital camera or a scanner to your computer on a temporary basis, you won't have to fiddle around the back of the machine... the inputs are right on the front panel.

Also, it you want to take a memory stick or card out of your camera and have it read directly from your computer, the HP has slots for them right on the front panel... again, just a matter of convenience. Lots of computers do not have these slots built in.

The HP also has inputs on the front panel for a microphone and headphones. Most computers have these on the back of the machine.

These are all strictly convenience features. As for performance, I would say that will depend on how you have your computer configured regardless of brand.

If you want to do some research, you can check out PC Magazine at http://www.pcmag.com. Another great site for reviews is http://www.cnet.com.