I've yet to do dim sum at either—Denver hounds, it's time for another outing!—but since about half the folks I respect prefer the one and about half the other, I'm trying to figure out why. My SO the Director just said "whities" ("whiteys"?) prefer SS, which just won the Westword Best Of award, whereas Asians prefer King's Land. He's Scottish or something & prefers KL.
Of course the implication is that KL is more "authentic," whatever that means as usual. I'd really like to know the difference with respect to both range & execution of dishes. rlm & I have specifically discussed chive dumplings, for one thing.