Phoenix has more of a “stripper” look, tanned skin and a bunch of tattoos. Holly has a more natural look, even though both have manmades. I’d say phoenix has a slight better body - mainly because of her ass - and holly is slightly prettier.
As far as service goes, they’re pretty much equal. They’re both great kissers, very friendly and great in bed. Phoenix offers some extras like cimws, Holly doesn’t as far as I know.