For real-time
odds calculations, I like Holdem Indicator alright. It doesn't have a HUD per-se but it does attach to the bottom of your table window and tracks players and their stats there.
Here's a video review of an older version by Poker Calculator Report:
YouTube - Holdem Indicator
The latest version has side tabs on the left side to either show the player stats in the main window, or to break them out into an undocked, separate window as shown in the video.
I got it "free" by signing up to SportsBook through them and playing 200 raked
hands (until then it's locked to the room you signed up for). In fact I'm not even sure they sell it otherwise, at least I don't remember seeing an outright price for it.