I'm stuck with QWERTY, but have been tempted to try Dvorak. Dvorak advocates claim it's faster.
Are there any studies that compare these two (main) keyboard layouts? Are there other layouts out there that are more productive than these?
If you are already used to a QWERTY keyboard and you feel that the benefit of changing (which doesn't include speed) will be worth the time taken, as well as not easily being able to use someone else's keyboard, then you should take a look at the Colemak layout.
It has fewer changes from QWERTY than Dvorak, and keeps the position of many of the shortcut keys in particular (cut, copy, paste). In tests, it is as good as Dvorak in terms of finger distance travelled (in English) and moves high frequency keys from your small fingers (which is a weakness of Dvorak).
Overall though, there is little evidence that Dvorak or Colemak is faster than QWERTY (see http://hi-games.net/typing-test/ as an example), but there is evidence that it helps with fatigue, RSI and carpel tunnel syndrome.
Fun fact: It's a common misconception that QWERTY was designed to slow down speed - one held to almost as doctrine by many people. It was designed by Christopher Latham Sholes based on a letter frequency study (by Amos Densmore) and some general trial and error to prevent key sticking. It did this by alternating left and right hands (which is what helped with keys not sticking). As it turns out, his also happens to help with faster typing, and is exactly what most other layouts also do. (For a speed comparison between different layouts, see http://hi-games.net/typing-test/)
In fact, a major study in 1956 conducted by the U.S. General Service Administration found Dvorak to be no faster than QWERTY. This was followed up by other studies into the 1970's all confirming the 1956 study.
Yes, there are studies that claims that Dvorak is faster than QWERTY.
It's based on total finger movement that is needed to write common English words. So the Dvorak layout has the most frequently used characters on the middle row, and the rarely used ones on the top and bottom row. Ergo, you don't need to move your finger between the three rows, but you can keep hour hands on the middle row most of the time...
According to this video, you can write 120 words on the QWERTY home row and 5000 words on the Dvorak home row. On QWERTY you are off the home row more than 70% of the time, and on Dvorak you're on the home row 70% of the time.
You'll find some documentation on Wikipedia:
You'll find some test here (including other keyboards):
And some scientific research here:
Fun facts: (Read: "the QWERTY Legend")
The QWERTY layout was actually designed to slow down the writers speed. The reason for this is found in the design of the old typewriters, where you wanted to avoid entangled typebars as a result of several keys being pressed simultaneously (or to rapid). So the the keys were layed out in a way that forced to alternate the key pressing between the left hand and right hand.
It should be added that Sholes' main goal was to speed up the overall writing, but to increase the overall "words-per-minute" measurements, he had to avoid those key clashes that resulted i a total stop for the typist. So, his solution to increase the overall writing speed was to avoid key clashes and thereby get the typist into a steady rhythm with alternate left and right hand pressing.
(It is also said that the keys you need to write "typewriter" were put together on the top row, so that you could demonstrate how fast you could write "typewriter" to a potential customer. Funny? - Yes. A fact - I doubt it:-)
When I get a downvote with no further explanation, I usually re-read the question and my answer to figure out where I was wrong. I'm not sure about the downvote in this case, but I guess my answer could be read as an ardent advocate of Dvorak. That is not the case, so let me clarify a few points...
Re-reading your question, it is kinda vague. It's quite a difference between "does any research exist" and "is Dvorak better". So, let's just take them one by one:
Q: What are the benefits of non-qwerty keyboards:
Statement: Dvorak advocates claim it's faster.
Q: Are there any studies that compare these two (main) keyboard layouts?
Q: Are there other layouts out there that are more productive than these?
OK, some subjective conclusion, then:
My understating of your question is that: You want to find out if another keyboard-layout can do some improvements on your everyday effectiveness.
My subjective answer (without any supporting research) is: Yes, another layout could improve your effectiveness - but you're on the wrong track!
IF your main task is to write loads of text AND you don't mind to spend at least a month of training AND you don't mind to exclusively use the chosen keyboards layout, then you might consider to try something else. Otherwise stick to QWERTY!
But you should definitely try different QWERTY keyboards!
So, take a look at these:
Natural Ergonomic Keyboard 4000
Logitech Gaming Keyboard G510
Logitech G13 Advanced Gameboard
For the programmer
I use Coffee++ since 4 years. It is a keyboardlayout for typing with just your left hand. Optional you can use the right hand in addition to speed up typing. But mainly the benefit is, that you can have your right hand free to use the mouse, telephone or drink some coffee ;)
Coffee++ is optimized for programmers so all important characters are accessible directly without shift. And they are also accessible with just your left hand, where the CAPSLOCK-key is used as a second AltGr-Key
If you are already used to type 10-finger QWERTY really fast, then typing speed builds up quite slow, but I thought it is an effort, that I will benefit from the rest of my life.