I've been typing using Dvorak for a year now. Pre-switch querty was about 95wpm. Test today says 102 sober, 93 drunk. Not too bad.
Vim took a while to get used to. I didn't map everything so that the positions were the same - I actually learned the new positions. So the hjkl is not exactly the same. The only major change I made was that cw is mapped to cg (looking at your keyboard, that mean that change word is 'iu' instead of the harder-to-type 'i,'.
Starcraft was tricky until they allowed custom key mappings. Prior to that I had a hotkey to switch back to qwerty for that game only. My story won't be the same for others though - I play with the grid set up and a lefty mouse, so I'm pretty unique there.
The iPhone hasn't bugged me - the keyboard is too small for the different layout to compete. The ipad is a bit more troublesome but not really - I'm typing by sight there anyhow. Bluetooth keyboards connected to iPads can use Dvorak anyhow - it's just the software mapping that doesn't support it.
Switching was really only bad for a month, I'm faster (if only slightly now than before), and it's working out pretty well. If this means I'll dodge the repetitive stress so common for folks in my industry, it's worth it. Of course there's no real way to tell...