First of all, Barcelona is a great place to visit, and we had our usual wonderful experience with Untours. Our transportation from the airport was seamless, although we had to wait a couple of hours before we could get into the apartment. Even when we got in, we had to wait for the cleaning staff to finish, so it was after noon when we were finally able to settle in and take a little rest.
My husband and I stayed in the Catalunya Suites for two weeks, and the location couldn't have been better. Walking distance to many of the popular sites, and a number of Metro stations were within a few blocks. Public transportation was very easy to navigate, even before we had our orientation with Adriana.
As far as the apartment goes: Overlooks Ramblas de Catalunya, a major shopping district. There are several outdoor cafes in the wide median of the street, so it's a good place to people-watch both from the apartment and sitting in a cafe. The kitchen is well-appointed, with a full-size fridge. It was nice to have a safe to keep extra cash, passports, and credit cards.
The second bedroom can hardly be called a bedroom, but it worked out great for the two of us. We spread clothes, etc., out on the twin beds because there's not a lot of storage space in the apartment. It was nice to have the two bathrooms so we could each have enough space for our 'stuff'.
The apartment management representative who acquainted us with the apartment was helpful. He gave cursory instructions for the washer (which he said was also a dryer), but since we didn't use it for several days, it would have been very helpful to have the instructions in English. It was a very frustrating experience to try to use it, and although we thought we had it figured out, we could never get the dryer to work. Believe the Untours website when it says that there's a washer, no dryer.
The ARTicket was nice, but you really have to be a fan of modern art to enjoy the museums. We're not so much. I think we missed the best one, because the day we went to Montjoic, by the time we finished the Miro museum, we were tired of it, so didn't go to the museum of Catalan art.
Adriana was very friendly, and easy to work with. The orientation was excellent, and the day we went to Santa Catarina Market and had the tapas lunch was a lot of fun. We didn't need to contact her, so we didn't hear from her again until the day before we left when she called to verify our airport pickup. Again, that went very smoothly.
I don't have any reason to discourage anyone from the Barcelona Untour, and I really feel like you need two weeks to see the city without totally exhausting yourself. Have fun!