Ranked in these QuestionsQuestion Ranking
Pro Good for vim users
Qwpr is pretty close to QWERTY, and even the HJKL keys are in the same left-to-right order (though on different rows). Alternatively, the AltGr plane also has arrow keys in a sensible position under the right hand.
Pro Common shortcuts don't move
A, Z, X, C, and V are in the same positions as QWERTY and Colemak.
Pro As easy as Dvorak
It's 32% easier than QWERTY by the Carpalx metric, which is slightly better than Dvorak's 30%. This is probably within Carpalx's margin of error though.
Pro Alternate plane with CapsLock key
CapsLock is pretty useless for most people, but qwpr layout uses it to shift to another plane with easy access to punctuation and arrow keys. This is especially useful for programmers.
Pro Minimal retraining from QWERTY
11 keys move, but except for P and E, they don't change fingers.
Con Puts E on the pinky
'E' is the most used English letter by far, at almost 13%. That's almost as much as the spacebar. It needs to be on a strong finger. The pinky is the weakest finger and on the right side it is already overtaxed from Ctrl, Shift, and Enter.
Con P and E change fingers from QWERTY
Which makes it harder than necessary to learn from QWERTY. (And makes no sense. 'E' was arguably better in its QWERTY position on a strong finger.) This is due to using the flawed Carpalx effort model.