I was going to nerd-out and write a lengthy, detailed dissertation on the benefits of an internal water heater in front load washers, but then I remembered this post at GardenWeb which does an excellent job of explaining the benefits.

I would add my own experience.

My Maytag Neptune featured an internal water heater, and I found myself using the hottest wash cycle far more frequently than I thought I would. The heater allowed the washer to do an amazing job on getting items clean that I thought were shot. White t-shirts came out blazing white. Stinky, mildewed towels that I left laying outside came out fresh. Sneakers covered in grass stains came out looking almost new. Khakis that I thought were ruined by grease stains were saved. And not once did I ever use bleach in my machine.

If you are considering a front load washer, I would highly recommend you get a model with an internal water heater. You will only spend $100 to $200 more over the base model (including a few additional bells and whistles), and you will quickly realize it is a very useful tool.