The 870 is a fine gun, but the overbored barrel on the 835 is hard to beat. I have an 835 with a Hastings extended turkey choke tube. It is a turkey thumpin' machine.
I haven't had any trouble with my 835, but then I only use it to turkey hunt. It only gets fired one time a year. I use the 3.5 inch Winchester supreme #4's. Either gun is a good choice. The 870 will probably wear better than the 835, if you plan to use it for everything. I still like the 835 barrel.