On my RX 580 cards Claymore miner 11.5 still a bit faster. About 0,25-0,5%. His fee is 1%, Phoenix is 0,65. Result is no difference.
Phoenix gives much more rejected (staled) shares than Claymore's...
Continue to use Claymore...

Add an option like -ttli in Claymore. It enables low intensity mode on reaching pointed temperature...