to others: feeel free to correct me if i'm wrong, but:
in my experience, sprung crowns, as they are slightly wobbly by design, when paired with a standard rep crown guard (which is not perfectly designed to strike the crown at dead center every time) can produce a crown that, when simply locked in normal fashion, will be slightly crooked (generally, with the crown facing slightly inward towards the dial on the 12 o clock top half). - this can be fixed by fiddling with the crown, but it's an annoyance. It might be only a few degrees, but, to my eye, it's noticeable. Additionally, if you are showing someone your watch, and you open and shut the CG, your crown will be locked out of straight -- a dead giveaway.
It can be mitigated with reshaping of the CG lever, which i've done, but it still can occur from time to time.
Watches that i've had with unsprung crowns have not had this issue, as there is not enough play in the crown beyond a miniscule flex of the stem to allow this to occur.
Watches with 1950 style crowns (which are unsprung and come to a point at which the CG and crown meet) are 100% immune to what i've described above.