Why ? The gtx 690 is faster but lacks some memory .. 2gb vs 4gb..
The 290 is a 1 gpu card vs the 690 being an dual gpu card but with a older chip (2x the chip of the 680)
So if you want to be future proof choose the 290 or just wait for the 390/x to come out and then compare to the gtx 980 ..
Both cards are good but don't have the newest technologies ..
I would just wait or get a 970 instead or if you can afford the 980