I HAVE an MSI Gaming R9 390 and it is a great gpu. It is about the same as an RX 480 (sometimes surpassing it sometimes around 5% of the performance). I keep mine clocked at 1100mhz on the core and 1550mhz memory with 30% power limit increase and no added voltage. It consumes about 200W on full load but produces a lot of heat (275W TDP gpu). Make sure to set a custom fan curve to keep it cool. I tend to open the side panel of my case when playing demanding games as heat tends to built up even though I have good airflow. At that price it is a good deal over an ~30% more expensive RX 480.
However, for you budget right now you can get a GTX 1070 although I recommend you to wait a couple more weeks becasue AMD is launching AMD Vega and even if the flagship would be over your budget, prices should go down on both Nvidia and AMD gpus. WHat are the specs of the rest of your system so I can recommend you sth more specific. Do you have a g-sync/freesync monitor? Do you intend to buy one?