Any multi-link suspension seems to eat bearings in hard use. Be it a Santa Cruz, Giant, Mondraker or whatever.
I’m planning a lot of hard riding this year (given up the 9-5) so have gone with a single pivot Empire for this very reason.

Similar issues with my bike too but way less than 600 miles
http://singletrackworld.com/forum/topic/bearing-trouble

more than fair I’d say, those bearings have a crappy life down there. Not sure if spectral have the same plain bearing as the nerve, but I got the feeling regular dismantling and cleaning could make them last a bit longer, though it is pita. canyon seem to spec greasable ones, but provide self lubricating replacements, or the other way round, I forget now.

Not a lot of help I know, but I pulled the bearings on my Five at the weekend for a bit of PM. Despite 18 months of riding once or twice a week in all weathers up here in the North East of Scotland I was pleasantly surprised to find that they were as good as new. Maybe our sandy/peaty crap isn’t as tough on bearings as your gritty muddy crap, but I’d certainly be a bit miffed if they were failing after only 600 odd miles.

Although I though only the main pivot ones, most of the original bearings in my Giant had failed when I disassembled it after 18 months of very light use.
I replaced them all with Katec ones and put a BETD top shock bush it whilst I was at it, as the original had become a bit sloppy.
Five years on and the bike has done at least 5000 more much harsher miles in that time, the shock bush has been replaced again, but the bearings are still ok. Perhaps I’ve been lucky.
Winters round here are a gloop fest too.
EDIT.
Don’t always clean my bike straight after a ride and adopt a hot water, bucket and brush approach when I do, just using the hose under low pressure to rinse it off.
Quick gentle squirt over with GT85 ( heaven forbid ) , cover brakes with a bag while doing it, just to push out excess water, go make a brew, back to bike wipe off all the excess, lube chain, drop of fork oil round wiper seals on shock n fork, cycle suspension, wipe off excess oil from stantions. Lock bike up. Go and have tea.

Some info about the MAX type bearings

Enduro Max Type Rubber Sealed Deep Groove Ball Bearings: These types are manufactured with rubber seals inserted into the outer raceway and in contact with the inner race providing protection against the ingress of moisture, dust and other foreign matter and serve to retain the pre-filled grease in the bearing.

MAX Type bearings have no cage and a filling slot for the balls. MAX stands for Maximum Balls possible in the bearing which is achieved by using the filling slot to insert the balls, the balls are effectively next to each other.

They generally have a 35% more load capacity than caged bearings. MAX bearings do not spin as smoothly as the cage bearings and should in general be used for suspension pivots or problem areas where standard bearings wear out prematurely.

Static Load capacities are limits well before deformation of the bearing and are conservative.

Always install bearings by pressing on the outer race only into a housing with a fixture that is a close match to its diameter, never knock bearings into their housings with a hammer – premature bearing failure will occur from knocking bearings into housings. With max type bearings in application like suspension pivots try to position the filling slot at 90 degrees to the loading direction where practical.