While a HUD is interesting, it is only a reference. Seldom should it do anything more than giving you another piece of info.
I've had one a long time, and really I prefer the sites where it doesn't work because it is so easy to be swayed by what I think it is suggesting.
Where a HUD does a lot better for me, is figuring out how a player that I have a lot of hands on is playing today, compared to how he usually plays. If over 1000 hands I have a players lifetime stats showing him a 20% VIP, and then change the display to session and see he is playing 40%, and his other stats have jumped too, well that tells
me he is either drunk, or pissed at something in his real life.
THAT gives me more useful info than how he played last month.
Point is you generally need a lot of hands on particular players to make any useful decisions based on those HUD stats.
If you have a good number of hand with any player, you should have some notes on them. And those notes are usually better info than a HUD is. Or they should be. Just note that he did this or that, and if you think but are not so sure about a observation, add a ??? after your note, then if he verifies it, you can remove a? or 2.