I've been using claymore for my RX X80s for over a year now. Decided to give phoenix a go...and I'm damn happy I did: slight improvement in hashrate at the same clocks and power and significant reduction in stale shares! I've been suffering from 5-15% stales (ethermine.org) since Byzantium fork in 2017. With phoenix I have <1% stales.
Great job, man.
Retraction of my previous statement: number of stale shares is marginally lower than claymore's. During the first few hours of running phoenix I indeed had <1% of stales; number increased with time though and as of now I'm back to 5-10% stales.
Bad job, man!