Being a little biased as I was born and raised in Sonoma, but if you had to choose just one, I would say Sonoma. It is much more quant, quieter, and not as crazy as Napa is.
Some things to remember:
- Napa charges for wine tasting (usually something along the lines of $4 to $6 for a couple of tastes), whereas Sonoma typically does not.
- Sonoma is much cheaper then Napa. It is cheaper to stay, cheaper to eat, and cheaper to play.
- Much of Napa is freeways, and the downtown area (which IMO is not the nicest town). Once you leave Napa (go into Yountville, St. Helena, Rutherford, Oakville it is pretty) but rather expensive.
If you could, do both. It is worth it. But get a hotel in Sonoma.
Just PLEASE dont slow down on the one lane highway to take pictures of the vineyards, the locals want to shoot you at that point.
