I've used both TRM and Phoenix.  In my experience, TRM works better on RX5000 cards than the RX6000.  I get better hash rates with my 6800s on Phoenix with same power usage. I get better hash rates on my 5700s in TRM at lower power than Phoenix.  I also like that fact that Phoenix allows me to control the cards power, clock and mem without 3rd party software and radeon wattman.  I also think the remote management is better.  You can restart the miner remotely with Phoenix.  With TRM you gotta kill the app and start again from the desktop.