I like my Nexus 8 I've had for about 6 years, but last year it failed, locked up, and stranded me.
I'm a heavy rider, but keep higher rpms and never stand on it. I had done the biannual oil dip and bearing grease, weeks and a couple hundred miles before, and it just started clicking and then locked. My confidence in it is gone.
I opened it and one of the pawls had a piece cracked off it, which grabbed and destroyed the retainer rings, and locked the carrier to the hub. There was very little apparent damage to the internal ratchet of the hub, which is milled directly out of the hub aluminum. I thought I could just get some new pawls and rings and put it back together.
Those parts are apparently not available, except salvaged from other dead nexus hubs. Bummer.
I put it back together with 3 pawls and fixed the rings and it rides, but I have no confidence in it.
My local LBS (performance and consumer) cannot locate identify even the complete carrier from the Shimano catalog.
The feature I really liked was the ability to up-shift at a stop.
If the new roller clutch version is less likely to fail I will consider it, but I'd like shimano to give me some purchase credit on this old one. A I have 50 year old Sturmey's that I got for free that still work perfectly.
On second thought, I think I may just lace up a sturmey and put a second ring on the crank for a Fixus 6.