I've got 4 rides on my 2011 Boxxer WC, and lovin' it. A few things you need to think about the Boxxer.
1. More adjustable then either the Fox or the 888. Having seperate rebound settings (ending and beginning stroke) is HUGE in my book. I can dial the fork to feel exactly as I like with less compromise.
2. Air spring tunability. With your weight, the air spirng will help you dial in the right amount of sag and feel that you just can't get from a coil. The new WC Solo Air spring feels superb, with a great mid stroke, and beautiful ramp up. It is uber plush as well. I'm 180lbs, and run 55psi according to my pump.
3. Ease of service. The Boxxer, and RS forks in general, are very easy to service. It takes minutes to change the oil bath, and the sealed damper fluid needs to be changed minimally.
4. Great CS from SRAM IMO. I am more confident in SRAM to solve any issues I may have more quickly and cheaper than the other manufacturers.
5. Lighter than both, and it is noticable.
6. I can't comment on the durability of the fork as I just don't have enough time on it. However, I have been rocking a Lyrik Solo Air DH for a while and it is great. The Boxxer Solo Air is very similar, and exceptionally simple.
7. I agree with above poster, you know your budget and desires, do what you want.