I really like fixed axles, especially when maintaining my fleet of bikes for the family. They completely eliminate the axle to arm interface issues and in all my cases definitely a lighter total package. However I've upgraded because of the maintenance improvement, not the weight. I've used them all and they all are good; hollowtech, GXP, Campy. In some cases I do wear the outboard bearings out quicker, but it is because I'm power washing some of our MTB and cross bikes. $20 to replace the bearings.

What I don't like, and I think is a step backwards, is press-fit s**t. PF30 and BB90 all seem to eventually start creaking. So I stick with threaded BB bikes whenever possible.