I learnt Dvorak 6 years ago and now type exclusively in Dvorak on QWERTY keyboards (currently a Microsoft Ergonomic). I have never used a keyboard with a Dvorak printed key layout. I think my Dvorak typing speed is still slightly slower than my old QWERTY max, but it feels much more comfortable typing for long periods, and less effortful.
The printed keys don't mean much - to learn to touch type correctly you shouldn't be looking at the keys anyway. I used a few typing games to start and then switched cold turkey for a few activities that didn't require speed (like responding to emails). It was, indeed, very frustrating.
That said, I don't recommend switching for most people, because you will get much worse at QWERTY and when you occasionally need to type it (like on a colleague's keyboard) you will appear incompetent; you will ruin your muscle memory for keyboard shortcuts; and, because standard Dvorak is not great for programming IMO due to the position of the [{ and }] keys. But now I'm in too deep, and I know from experience how hard it is to switch so I don't want to switch back!
I switched to Dovorak maybe more than 15 years ago. But I found it put too much load an the pinky fingers (which already are pretty loaded doing enter, backspace, shift). Also typing german is very awkward with Dvorak.
I then switched to NEO layout [1] which is optimized for german, programming and english. I never regretted that. For programming, NEO is superb. It gives you 3 different shift keys (each present two times on both halves of the keyboard) thereby allowing a lot of punctuation and other special keys being typed blindly without much moving of the hand.
Switching back to occasionally work on a qwerty keyboard was impossible at first. But eventually I got used to that and I can now go forth and back and adjust within minutes. Though qwerty typing speed and accuracy is much lower than my NEO speed and using qwerty generally feels frustrating.
The printed keys don't mean much - to learn to touch type correctly you shouldn't be looking at the keys anyway. I used a few typing games to start and then switched cold turkey for a few activities that didn't require speed (like responding to emails). It was, indeed, very frustrating.
That said, I don't recommend switching for most people, because you will get much worse at QWERTY and when you occasionally need to type it (like on a colleague's keyboard) you will appear incompetent; you will ruin your muscle memory for keyboard shortcuts; and, because standard Dvorak is not great for programming IMO due to the position of the [{ and }] keys. But now I'm in too deep, and I know from experience how hard it is to switch so I don't want to switch back!