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!