The best HUDs are entirely subjective, find one that you like to look at and can easily get information from mid-game (you don’t wanna lose track of your own health or uber %). There are MANY HUDs out there with different artstyles and aesthetics - you just need to find what suits you best. (aHUD by Nokk - HUDs.tf page | Imgur Gallery)
Some people want a scoreboard optimized for 6v6, and that’s just fine.
(RaysHUD by RaysFire - HUDs.tf page | Imgur Gallery) Some people like more centralized information and health crosses, and that’s just fine. Some people have gotten used to the health and ammo being at the corners by default, and that’s just fine. While this can be good for vision, it means you have to take your eyes off the center just to check your health and ammo - which just might lead to a quick death. The Default HUD (Heads-Up Display) for TF2 is very small and has most of the information anchored the corners. The other day, we posted about headsets and the available alternatives for voice communication, and then how there would be a post about custom HUDs and crosshairs and such.