-- Very light, and slim , even with hood~
-- Focus fast.
-- Good PQ, excellent color !
-- Excellent built, even better then canon L lens IMO, perfect match for K-7
-- 21mm, excellent for snapshot, especially with K-7 or K-X
-- Good design of len hood, small, can carry a filter inside which will not affect the size and the appearance of the len.
-- The size and the overall design of pentax DA limited series really make m4/3 ashamed.
-- F3.2 is a bit small, but wide angle with this size, nothing to complain.
(actually it's just half stop slower then F2.8)
I have DA16-50, DA50-135, DA21, FA43, DA50-200
I mounted DA21 on my K7 more then 80% of the time.
I always take this len with my K7 only in my bag.
I thinks this is a must len for pentax user, to experience Pentax's excellent built quality, extreme small size of pancake, very usable wide angle for snapshot, and perfect color reproduction. This is what other brands cannot give you but pentax.