I had seen the 700P 5R for a lot more money than the Gen2 and Gen1 Stainless, but then for a while late last year, there were links to deals for those 700P guns under $1k, and I can only imagine that various supply houses were dumping excess inventory to flush out by year's end.
Now, as far as differences, the Gen1 doesn't have cerakote, tactical (large) bolt knob, nor does it have fluting.
The Gen2 has all those things, thus the upcharge. The real differences that I see off the top would be the fluting on the Gen2 and the 40x trigger on the 700P. The rest is just aesthetics. ETA** Badger 0 MOA rail on the 700P, which could be a plus or a minus depending on what your end goals are--it's nice to have a rail on there from the get-go, but if you truly expect to reach out (1000yds is usualy the benchmark) you'll need a rail with some MOA built into it, especially using a .308.
I found a used 300 Win Mag in the Gen1 configuration, and got it because I couldn't beat the price. Otherwise I would've opted for the newer Gen2 version because I really like the looks of it, and would like to have a slightly lighter gun (accomplished with the fluting.)
I really don't think you would be disappointed in whichever model you chose, honestly.