I have stayed at the Diagonal mar. I agree it is a bit further out, however it is a really superb hotel. It has an outdoor pool open from May to October, and a great executive lounge. The rooms and reception/bar areas are very modern and well maintained. Accross the road from the hotel is an indoor shopping mall, with plenty of places to shop, eat and drink. There is also a bus stop accross the road from the hotel. There are regular buses to Playa de Catalunya, trip takes about 35 minutes and costs bout 2 Euro's.