The Unit ID display feature works good on mine (I have the Mode 2 (Unit ID Mode)) selected and have the 3 line display off.
If my scanner doesn't capture the first part of a transmission on a P25 system, the Unit ID doesn't always display. Also there are some talkgroups patched to VHF & UHF frequencies and Unit IDs do not always display.
I've also set up Alpha Tags for 1,100+ IDs and the alpha tag function works well.
So once you get all your settings in place, I'm sure you'll be happy with this feature!