I had to wait more than 10 months for official Gingerbread to come to my Galaxy S (Epic 4G), but in the case of ICS not even the Nexus S 4G is on board yet so I wouldn't really fault Samsung or be so quick to buy a Nexus device in this case.

Depending on which Galaxy S you're on, look into CM9. Despite its early stages, it's amazingly stable. I've been on ICS without any problems for awhile now.