I’ve heard mixed opinions about this – yes, stainless bearings are not as hard as regular ones, but quite often when I do an autopsy on an old set of non-stainless bearings, I find a fair bit of corrosion inside, which softer or not, will certainly have ended their life earlier. I think it’s all down to where you ride – if you spend a lot of time very wet, then stainless bearings may well last much longer due to their natural corrosion inhibiting properties.
Personally, I’m still using Enduro Max bearings and, as stated above, always repack them with thick-ass, waterproof agricultural grease (Lucas “Red n Tacky” here). It doesn’t really matter if they barely turn afterwards – for linkage bearings, it’s far more important that they are full to the brim with grease rather than free-running and their life expectancy will be increased accordingly.
One thing that I’ve seen quite often is incorrect bearings fitted to linkages, where the LBS have used regular, off the shelf bearings, instead of specific max-load ones. In one particular bike, they fitted cheap-ass 2RS (i.e. fully sealed) bearings on an Intense which has grease ports to inject grease into the bearing itself. Obviously, the injected grease couldn’t get through the seals and the bearings lasted less than 6 months. Grrr.
One other tip – regularly service them – just whip off the bearing seals, clean ’em out and regrease them. The magic trick here is to rotate them a bit (hard to avoid anyway when greasing) so a different part of the bearing will be in use after reassembly. About an hour’s work for me on a typical VPP bike and I do this once or twice through the winter.