I liked it.
Seems I am in the minority though.
I love wine, and am a Bay Area resident, so it's interesting to see this take on Napa wines being put on the global map.
I'm not super familiar with Montelena (yet), but on a really minor note, Stag's Leap has always been a favorite of mine and it was great to see them mentioned in the final scene.
It's apparently not very historically accurate...but, entertaining none-the-less.