F-series has a better all around suspension... no doubt, especaily if you get the snow pro. Pretty sure they come with a fox floats up front and have a massive 1.375" track which is good in powder but crap for top end. Power wise with a stock viper woudln't be able to keep up to an f-7. The stock track and suspension on a viper just doesn't hook up as well and is down about 15hp from the firecat
The f-cat also will weigh a bit less... however i would never say that the viper has more issues then an firecat, never!
Firecats, and arctic cats in general wont have as smooth of an engine as a yamaha tripple, nor will it be as reliable, or get as good of gas and oil. I know a f-7 who has been in the shop 12 different times this year, each for a different reason NO JOKE.
For jumping and everything, i would have to say go with the cat if your set on one, (if you want a snowcrosser go Ski-Doo in my mind im not a cat fan) but there is a reason they dont hold there resale as well as a yamaha...
My cat esperience 2 sleds, 4 blown engines, all work down by the dealer who i know is a good mechanic i have known him forever......my .02
Also the first year f-series is something to stay away from, which is think is the 03'. I know all my friends who have firecats who got them in teh first year had major major issues within even the first 10 miles!