A big problem with HUD that I experience in my wife's Prius and in my former BMW 535 was that it was not visible with sunglasses on! Why the engineers can't fix this problem is beyond me;(
This was an issue with your sunglasses, (as someone who has had BMWs with HUD's almost as long as they have offered them). The issue is your polarized sunglasses had the polarization on them in such a way that it made the HUD disappear. The "fix" is either buying non polarized sunglasses or finding a brand which has the polarization NOT in sync with the HUD.
I forget now which brands worked fine with the BMW hud at this point, but my sunglasses work just fine with the HUD in my wifes X3. A factory HUD is something I would have paid extra for, as once you get used to it, its very convenient. One issue with BMWs implementation is, you can do "too much" with it. Changing songs in media, etc, makes you look "at" the hud the same way you would be looking "at" a screen. Your eyes may be forward but your attention isnt.
Back to tesla....
As some people have said, the speedo isnt an issue, BUT stabbing the screen while driving is basically a non starter. You have to look at the screen way too long to do that, and focus on it. At this point, I wont do anything that requires me to touch the screen while in motion. I use voice commands (which work surprisingly well for almost everything I would want to stab at the screen for), but wont touch the screen unless:
1. I am stopped at a stoplight
2. I am using Autopilot / NOA and can spare the couple seconds it takes to glance down at it.
Full disclosure though, I am also a person who will not touch my cellphone once the car is in motion. I send and receive text messages via voice commands with my hands on the wheel, and wont touch my phone for anything else while driving.
A few things benefit from having buttons, but that also could be because I have used BMWs iDrive interface in some manner or other for quite a long time.. almost as long as they have had it. Even after 3 years of having my model 3, I miss having "a few" buttons a bit. I do NOT miss the instrument cluster, however. Every time I get in my wifes X3, it looks incredibly "busy" to me, except for the HUD.