I've played Far Cry 3, Battlefield 3, Crysis 2, Skyrim, The Walking Dead, Left 4 Dead 2 on Windows 8 with no issues, so I think any "Issues with games" are overblown. You should pick whichever one is cheaper IMHO - they really are very little difference, MS basically swapped out the start menu for a "start screen" metro interface, and added "metro apps" of which there are approximately none, so you use the same desktop apps you do on Windows 7
I recently made a few major upgrades to my rig (CPU, MB, RAM) and got my first SSD. After hearing some rumors, and out of sheer curiosity, I decided to give Win8 a try. To start off, I was thoroughly impressed with boot times. It takes about 25 sec to be fully operational and 16 sec is spent in the POST. Sadly, after my fascination with how neat Win8 looks went away, I seriously started hating the Metro UI, because it fkn sucks (AND I have a dual screen set up - fly out menues (hot corners) are a no no).
Long story short, after some research I found classic shell and got my start menu back. Games run fine (Currently playing BlackOps 2, Torchlight II and WoW). Paired with an SSD, Win8 is pretty good, however I would not recommend it over Win7. If you're curious - go for it (you might even like the Shitro UI). Other than that stick to Win7 (who buys software these days anyways?)
As for windows 8 vs 7, it's more a out learning it. I forced myself to learn, I'm a tech and would have to at some point. But I do a good bit of gaming. Sleeping dogs, chivalry, just cause 2, metro 2033, planetside 2 to name a few all run great. I have seen some things like our newest version of Symantec at work causes trouble with windows 8, our VPN client does not play nicely either as far as I'm able to see. All told windows 8 is liveable and does gaming just fine. If the look and feel is a big deal classic shell helps. I actually am forcing myself to use the start screen, but 95% of my time is on desktop or games. Windows 7 is tested and you know what you get. If on a budget windows 8 will do what you want and you can get windows 7 look and feel back to an extent with classic shell.