i used a FS carbon 26 wheel Felt Edict for 2 seasons and found that a) i enjoyed the suspension in our rooty trails here in western NY and b) that the thing is an expensive trophy wife in terms of upkeep. I'm doing most of my riding on a steel 26 in single speed bike now and might use the FS just for racing or might sell it.

The big expenses for me:

1) Carbon cracks in slow speed impacts with rocks or stuff in the woods and it's easy to break these frames. They can be repaired, but I have broken mine 2x so far and it gets expensive

2) The suspension bushings seem to wear quickly in muddy conditions. The are not overly difficult to repair, but now that my bike is "obsolete" i wonder how long I'll be able to find them

3) The rear shock needs to be serviced, every year they say, so add that to the budget

Lot of people do very well or win against geared bikes on single speed rigid 29er aluminum bikes around here, wide open stuff is where you get eaten up by people with gears though. For racing I'd be looking at something like a hardtail aluminum frame with about 100m of travel