What's your overall budget for this? I'm assuming you aren't limiting yourself to a $1,000-ish limit since you've looked into Fox and icon, but this will obviously play a large factor.

50k miles seems on a high end to expect out of an aftermarket shock I would imagine.. depending on the road you drive some OEM shocks are going to start the end of their life at that point.

I can't speak from experience, but would imagine the Fox and Icon shocks are going to give you the best ride quality. Sure, they may need "service" after the 50k mile mark, but I would guess that with something like the 5100 shock you'd just be outright replacing it by then anyway.

I am currently on the Bilstein 5100 shocks, OME springs for a 3-ish " lift and am happy for the money. As far as ride quality, I will say that I definitely did not improve it over my factory shocks I had. But my goal was to go up, not ride smoother. Long term my plan is to go with a more serious setup like the fox or icon.