Amazing pics! Barcelona is addictive - you will fall in love with it. The city has much to offer, the surrounding areas are diverse and worthy of exploration and the uniqueness of the cultural history will engulf you.
Barcelona is also a wonderful "walk around" city - with no agenda required and no daily plan to accomplish. I would give yourself at least one day where you wake up, have a coffee and just let the majesty of the environs wash over you. It is a special place. We were there five nights and could have easily stayed another five. It's a beautiful city with warm and friendly people. Loved everything about Barcelona! If you like wine, get
barcelona airport transfers or taxi and consider a day trip to the Penedès Wine Region; it made for a memorable experience. Madrid is one of my least favorite cities in Europe; didn't find it particularly welcoming to tourists; aggressive panhandlers; not a lot of charm. Full disclosure, we did not visit the Prado, because at that point we had toured enough art museums. The highlight of the Madrid stay was our day trip to Toledo.