For that setup 1000W is over kill. You could run two 980 Ti's on a 1000W PSU. Save some money and go for a 750W PSU, leaves plenty of head room for upgrading in the future as well. In my personal opinion you should only purchase brand new PSU's rather than used or refurbished ones, since it's basically the thing that can make or break your system.
Just my two cents :)
AMD is not bad. Ryzen just came out and out perform Intel on there 6700k and 6900k
AMD is a good budget system as this was the system i started out with and i was able to play titanfall and other games at high details including mortal kombat x which is CPU dependent. FX 6300 is not a great cpu but is good for a budget. I would recommend upgrading to 8350 or getting a ryzen cpu now.
R9 280xfx is great but just recommend getting rx480 now.
So AMD is not bad. There decent for budget system.