I've seen Samsung Galaxy S owners all over the map - GPS sucks - no you suck, GPS is great (infraction for name calling) - etc etc etc.
One thing is clear to me - last year, Samsung's PR department was in the news, quoted as saying they had a GPS issue and an update fix was coming in X weeks.
Then it didn't show. And then it did, and the flame wars started all over again - complete with lots of stories hereabouts about unhappy customer returns, "why I'll never buy Samsung again" ad infinitum.
I expect that Samsung MUST have learned from that PR nightmare and has simply fixed it now.
And with the barometric altimeter (I really couldn't resist) in the Gnex, the largest source of error on a small aGPS unit - elevation - is reduced, aka improved.
I think there's nothing to worry on with it.
And note well - when you get your Gnex, test the GPS even if you're not a big GPS user. It was my first indication that my new HTC phone was in trouble - turns out my GPS and 3G radios were both hosed.
Lemons happen with _every_ new product, so test everything when you get yours.