I just had to check this out, so we went for dinner last night. It is bigger, and it is prettier. The owner, Giorgio, came over and spoke to us during the meal, and I asked him what the relationship was to the first one. He says he is very good friends with the owner of the first Tavernetta, so it seems that this is really not a 'branch' of the first one, but sort of a distant cousin.
Now, the food; my DH had what he called the best seafood salad appy he ever ate. I had the special "white salad", lettuce, endive, mozzarella, and shaved parm. Hubby had the chicken marsala, which he loved, and I had the special roast lamb (I almost always order specials). I did not have dessert, but DH did, a beautiful looking berry tart. It seems the desserts are made off premises by a dessert company, except for the tirami su, which they say is homemade.
It's hard to compare the two. This is certainly worth a try, but it's competing with my memories of the vegetarian lasagne, made with homemade pasta, that I tried at the other place. This was still on the menu last night, but I'm now on a low-carb diet, so I didn't have any pasta. I don't know if I'll be able to get my husband to drive to #1, he was so happy with his meal at #2.
The only off note (literally) was the musical entertainment; the guy had some intonation problems, but if you go during the week, you can avoid the music.