I've tried searching for this but I can't seem to find much on it.

I've just picked up a pair of 3-bolt Sidi's and I'm looking for my first set of clipless pedals. I've narrowed it down to Shimano Ultegra's or 105's. Has anybody on here experienced the difference between them? If you read their descriptions the only difference I can find is that the Ultegra's have "Low-profile sole axle distance: 14.5mm" and are 8 grams lighter.

I'd like to believe that the Ultegra's are actually better for some reason given they are typically $50 more expensive