The same people who sneer at nearly everything Robbie Keane does sneered when he left for the US three years ago. It's hard to see how even they could be sneering now.
The general consensus among Sports Illustrated writers Grant Wahl, Brian Straus, Jeff Bradley and Alexander Abnos was that Robbie Keane was the best foreign 'designated' signing in the history of the League. Abnos was particularly vociferous on the point.
While Beckham propelled the league into a new era commercially, it took him a little bit to get his feet under him and play to the best of his ability in the league. Keane has had no such problems, and he doesn't show any sign of stopping anytime soon. Where other big-name signings have been aloof or disinterested (hello, Lothar Matthaus), Keane has been a consummate professional from Day 1.
Keane has changed the image of the MLS from being that of a nursing home for ageing superstars just looking to make as much money as possible before retiring into a competitive league that should be taken seriously.
For a league that is constantly seeking to improve its quality on the field, that is the best advertisement of all.
Straus agreed that Keane has been a better player for Galaxy than Beckham was, he argued that Beckham was the most important signing in the history of the League from a commercial point of view.
See also: The Ultimate Irish Football Continental XI