Recs.
Updated
Almost Dvorak, optimized for programming tasks. This layout retains the classic Dvorak number order.
SpecsUpdate
Pros
Pro Easy to learn if you're already used to Dvorak
The letter keys are the same, so it's not nearly the same mental jump as Qwerty to Dvorak.
Pro Better number arrangement
The smallest numerals are the most frequently used, so why should they be on the weak fingers of the left hand? The order still makes sense too. Odd numbers on the left, even numbers on the right, ascending from the inside out (with the least used numeral '9' in the middle).
Pro Don't need to buy another keyboard or move keycaps around
Having the original QWERTY labels is useful for other people using your computer or if you ever need QWERTY. Not having keycaps labeled in Dvorak forces you to learn to touch type. All QWERTY keyboards can be remapped to Dvorak in your operating system settings, so you don't need a physical Dvorak keyboards.
Pro Other people can't use your computer unless you switch it to QWERTY for them
Cons
Con Other people can't use your computer unless you switch it to QWERTY for them
Con Keyboard controls for video games and other applications are all made for QWERTY
If you want to game, the WASD keys are completely unusable. You either need to switch to QWERTY (and then switch to Dvorak every time you want to use in game chat) or spend time remaping every key, because games don't come with Dvorak keymaps. Sufficiently popular games might have Dvorak mods.
Con Dvorak users usually still use QWERTY on their smartphones
Dvorak is made for ten fingers. Its main ideas, such as maximizing the number of "finger rolls" and alternating hands, don't make much sense when you're typing with your thumbs.
Con Typing numbers is hard
Numbers are arranged for their characters, not in ascending order. You also have to shift.
Recommendations
Comments
Flagged Pros + Cons
Con Your QWERTY speed might decrease
Because after learning Dvorak you might never want to use QWERTY again except on your phone.
Con Moved punctuation requires longer adjustment period
Letters are moved, punctuation moved, and number in num lock are moved too.