I've had problems with debilitating hotspots since I started riding this past spring, except mine start to bother me at random times such as 40 miles into a very hard ride or 85 miles into a century. I had been on Bebop pedals (essentially Speedplays) and a bike shop fitter told me he was 95% certain my pedals were causing the problem, so I went searching for a wider platform pedal.
After reading a bunch of reports of Keos snapping at the axle I decided not to go with Look. I haven't crashed yet and I would hate to do so as a result of equipment failure.
The Ultegra 6620s I picked up are pretty damn nice. They have a wider platform and the cleats are nice since they have rubber tips which make walking easy. I have got used to the free float of my Bebops so I was afraid there wouldn't be enough float, but after setting them up correctly, 6 degrees happens to be just enough and doesn't allow my ankles to float too far.