Shai said:Because on a staggered keyboard, I don't think that the QWERTY "R" position is very good because it requires arching back the index finger, which I find quite uncomfortable.
 As mentioned in the wrist strain thread, I wouldn't put d on qwerty-r, rather on qwerty-e.  Thus:
q w d f p ...
a r s t g ...
This is essentially the polygon connecting Colemak d-f-p-g rotated one unit clockwise.  qwerty-e and qwerty-i positions are very easy to strike (I would call them virtual home), because of the long middle finger.   d is the most frequent letter among d-f-p-g, and it stands to reason that it should get the easiest strike.  The other three also get positions corresponding to their frequency, with the least frequent p getting the worst spot.  I really couldn't find a downside to this rotation after keeping at it for many days.
A bonus is this strengthens the claim that the layout that is easy to migrate to from Qwerty, since g stays put, and d and f stay on the same hand, same finger, moving only a row up.