I used ISIS for several years and had no problem with it, but many users have. It's definitely on the way out. FSA outboard cranks also have had their share of problems. One of the most common designs uses one center fixing bolt on the left crankarm and a tapered spline on the left side. There have been plenty of problems with those cranks. FSA resorted to recommending a specific loctite product for the splines and another for the fixing bolt threads.

ISIS BBs are really not serviceable, you just replace it if it dies. Pretty much the same for outboard BBs, although you can press out the bearings and put new ones in, with the right tools.

I don't think anyone can predict how long ISIS BBs will be offered. I'd either stock up on BBs now, or buy something that has a better future.

FSA has redesigned some of their cranks to use 6mm wide bearings instead of 7mm and added a wave washer to set the bearing preload, to eliminate the problems with some of their early model cranks.