the 970 tiger is $324 the 290 is $241. If you want the better deal then grab the xfx 290, I wouldnt get the asus since ive heard bad things about that card. However if you have a budget of around $330 I would grab the r9 390, the 970 or the 290x since those 3 all perform similarly. If you are going to be using a 1080p monitor, the 970 when overclocked will perform best most likely although it does have the 3.5gb and 0.5 gb slower issue. The 390 has 8gb so there is no problems there although the 290x performs about the same for slightly lower price.
390 $315 http://www.newegg.com/Product/Product.aspx?Item=N82E16814131672&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-PCPartPicker,%20LLC-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=3938566&SID=
290x $280 http://www.newegg.com/Product/Product.aspx?Item=N82E16814202145&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-PCPartPicker,%20LLC-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=3938566&SID=
Out of the 3 you mentioned, the 970 is the best, but the 290 is a better deal.