Most of all the two doors are very nice for multiple people or cross ventilation.
THAT seems like the biggest factor right there-------head room vs. two doors. Everyone's different (some more than others
), but I'll take the convenience/practicality of two doors in this size shelter, over the extra standing space of the Sawtooth. Several have already chimed in about the number of people that comfortably fit in each size tipi, and I'll just add that as with many backpacking tents, if you simply divide the occupant rating in half, you've got your comfortable limit--------especially since the wood stoves need space. If personal gear weight limits aren't a concern (or concessions can be made) then quartering the capacity rating makes for palatial accommodations. I bought a 4man primarily as a solo shelter that would still feel spacious if I took a friend. If I knew I'd be consistently camping with one or more friends, I'd go with the 8man in a heartbeat. It's an awesome shelter with true standing room, and again, two doors.
To me the 4man's one pole and two doors trumps the Sawtooth's two poles and one door, even thought there's a little standing room in the Sawtooth. Correct me if I'm wrong, but the wider footprint and lower profile of the 4man seems more wind resistant also. Maybe not an issue under most conditions, but it's still a factor to consider when dropping that kind of coin.