I'm just starting to learn the Dvorak layout (I'm at about 15 WPM touch typing after around 5 hours of practice over the last few days), but have not yet decided whether or not I will stick with it permanently. (Edit: After 2 weeks of using Dvorak, I'm up to about 35 WPM). This site has a useful trainer for learning it. Here are my thoughts so far:
- At the moment, Dvorak is painfully slow considering I type over 70 WPM using qwerty. Its probably not worth trying to switch to Dvorak unless you're willing to put up with it long enough get decently fast.
- I use the standard Windows keyboard shortcuts (ctrl-c, ctrl-v, etc.) heavily. Dvorak moves these keys to the right side of the keyboard, which is extremely inconvenient for people like me. However, there seem to be some good ways to work around this. I returned the shortcuts to their original locations by installing this layout, which was one of several solutions posted on this thread.
- After getting used to Dvorak, it takes several minutes to switch back to querty (which may occasionally be necessary). I've been using Dvorak almost exclusively for about 2 weeks now. I just took some 3 minute typing tests using querty and scored 25 WPM, 46 WPM, and then 55 WPM. I'm guessing I'd be back up around 70 WPM again if I typed in querty for a good 30 minutes or so, but I'm sure my top speed in querty will degrade some over time as well.
- So far, it does seem like Dvorak would be more comfortable to type in than querty. I have definitely noticed that many common digraphs are more natural to type in Dvorak.
- The more you type, the more potential for long term benefits. I type a lot, so I'm willing to put in a fair amount of effort for relatively small gains.
It's been a while since I wrote this answer, but if I remember correctly I stuck with Dvorak for a couple months. I used it almost exclusively for the first 3 or 4 weeks, and then switched back to qwerty for programming on my computer at school while still using Dvorak at home. I wasn't a fan of some of the places the symbols that are used often in programming got moved (like the semicolon). I kept using Dvorak at home and qwerty at work/school for at least a month or two. It was easy to switch between them since I used them both regularly, but I probably didn't get as fast at Dvorak as I would have had I stuck with it exclusively. I think in the end I got up to about 55 WPM in Dvorak.
I ultimately gave up on Dvorak at home as well because there were always small, annoying side-effects of using it that would crop up somewhere sooner or later. I refused to stick with normal Dvorak since it messes up ctrl-c and other shortcuts that I want easily accessible with just my left hand. I tried the hybrid layout I linked above that keeps the querty virtual key codes but remaps the character codes to Dvorak. That worked fairly well in most situations, but I ran into an application or two that I used often that ctrl-c was still messed up for (I don't remember which application). Perhaps that program used character codes instead of virtual key codes for its internal keyboard shortcuts or something.
So, I went looking for another solution that wouldn't have that side effect. I eventually set up an AutoHotkey script that remapped all the key-presses involving the ctrl, alt, or windows key modifiers back to qwerty. That worked even for the application that caused problems with the hybrid layout, but ended up causing problems in computer games. In many games, you hold ctrl or alt to do something (i.e. crouch) while pressing other keys. But, once I was holding ctrl or alt, the script mapped all the other keys back to qwerty, effectively scrambling all my movement and other controls. I could temporarily disable the script while playing games, but that's just another small annoyance.
A final gaming-related drawback is that you either have to remap all the keys for every new game (somehow they never have defaults for a Dvorak layout), or temporarily switch back to qwerty when playing games. Games like (Starcraft II) that have bajillions of keyboard shortcuts for every command/unit/ability in the game can be a real pain to remap.