Both cards are not on the same level of performance. The R9 280X is more between the gTX 780 and GTX 780Ti.
Yes overclocking on a R9 290X is limited due to being pushed already by AMD. Temperature issues are fixed by using non-reference gpu coolers, they are still fine but they do still run hot so make sure you have good case airflow i.e don't stick a R9 290x in a mini-ITX case.
The best R9 290X in my opinion is the Sapphire Vapor X cooler but other will still do fine. It was the reference design that had cooling problems. You can lower the temperature target of the card after install your drivers. This will cause your card to be able to run until you hit that temperature target and it try to stabilise around that temperature. Of course you lose some performance. It basically acts like Nvidia gpu 2.0 boost but you not overclocking your card.