I took my first trip to wine country in late April, and to get SPG stays had one night at the Sheraton Petaluma.
It's designed like a hotel you would see on a beach on the waterfront. Friendly, helpful staff who are well familiar with the SPG rules.
I was upgraded to a nice large corner room with a jacuzzi. (some of the rooms also have terraces to drink wine as the sun sets over Sonoma.) There was almost a little problem as I spilled a whole little bottle of bubble bath in the jacuzzi. Looked like an episode out of I Love Lucy!
The restaurant had decent food but the chef took awhile to get the steak done. I did not have breakfast there. The bar had a decent local microbrew.
I did not get to the Club Lounge (It was closed for a wedding reception.) There is a business center with one of those machines you put a credit card in to get Internet (I think $12 an hour.)
Watch the rates; depending on the time of booking they fluxuate all over the rate scale.
ALthough the Sheraton is NOT in WINE country it's a nice drive to the wineries.