I own both 7400 and 7600 rifles. 7400 is in 30-06. 7600 is 280 Rem.
Have used them in sub-zero temps, high temps (90 F), damp, dry, etc. Both reliable, both very accurate (more so than a lot of bolt guns that I've seen in use). Keep them clean (including the chamber - get a chamber brush) and LIGHTLY oiled with RemOil with Teflon, and you should have no problems with either. If going into very cold conditions, run them DRY. Leave them in a cold spot at night to prevent condensation. After the hunt, put a little oil on them. I have had multiple problems with both pump and BOLT action rifles in very cold weather (zero to subzero). Now run everything DRY until season is over when going into this kind of environment.
Recoil on 7400 is noticeably less than 7600.
Although they are both fast, the 7400 is faster. Tom Knapp is arguably one of the world's fastest shooters with a pump. Even he can break more targets with an auto than the pump (he's using a shotgun). For AIMED fire in the woods, very little difference once you've gotten a little practice.
Forearm rattle on 7600 can be controlled by picking the gun up just behind the forearm for the first shot, then using normally.
Both have potential problems with clips - but nothing that can't be remedied. See other postings in this forum if you run into trouble here. I have had no problems with feeding or clips and know nobody who has.
For any automatic rifle (Browning, Remington, AK-47, M16, etc), always orient the rifle with the gas ports "up" when cleaning. For a Remington, that means rifle horizontal to ground with scope down. This prevents junk from getting into the ports. Military guns have ports on top of barrel for this reason.
If you can, store the guns with muzzle DOWN, not up. This keeps oil from draining into action and gas ports. You'll notice when a bolt action is getting sticky. Same for pump. For an auto, this often goes unnoticed.
Both guns can be made to work, or not work - just like every other mechanical thing. I started with a levergun, went to a bolt, then a single-shot, and now hunt exclusively with pumps and automatics.
Hope this helps.