Mama Rosa is over in the Centro district which is also called 5 de diciembre. Just up the street from the arguably most famous restaurant in Puerto Vallarta (Cafe des Artistes ). Mama Rosa is a very traditional Mexican restaurant, a lovely room with great service.
The other place of "note" that I went based on many recommendations was No Way Jose. The restaurant ins on two levels. When I got there the downstairs street level space was empty save maybe one table, I asked if I could sit upstairs. The host was apprehensive and said I may have to wait 15 minutes as it was full, I said sure I'd wait. As a single person I didn't want to sit in an empty restaurant.
When it was clear that I was insistent on sitting upstairs the host said to follow him and we could see what the situation was upstairs. Against one wall is a small stage with a Mariachi band playing, the waiters are performing theater all over the room with flaming three tired drinks concoctions and the feel is very lively, most of the tables are large parties, but indeed a third of the seats are empty. The room has a hight clay tile roof and is very much a traditional rustic style Mexican restaurant.
The service was solicitous and prompt. The food thatI had mediocre. After the band finished it's set they wandered the room to go table to table to see if anyone wanted a private serenade (this is typical everywhere, but I hate it. I actually saw a guy who was having dinner with his girlfriend/wife and paid the band not to play and go away). All in all I felt this place was a typical tourist place selling an idea of Mexican food and culture, but with little authenticity.
In the end the two places that I ate at this year that really stood out were Red Cabbage and Fredy's Ocho Tostadas - Fredy's food was vibrant fresh and so delicious - the room bright simple down to earth. Red Cabbage has a sense of history both as a place and in terms of the menu. Very different kinds of restaurants yet they both share the same goal of serving high quality authentic Mexican food.