We stayed at Carlos' place in the old town for nearly a month. It's a very nice, modern condo, quite spacious, nicely appointed, and completely comfortable. It's also in a very convenient location, just off the Plaza de la Reina, so everything you'll want to see and visit is very accessible, you can walk to/from the train station, etc. There's only one downside: It's noisy. There's a bar/restaurant just 100 or so feet down the alley, and so there tend to be people out and about, sometimes making quite a bit of noise, late at night. If you're staying (as most people do) for just a few days, it's probably not that big of a deal. But for a longer stay, like ours, you may want to bring earplugs (which is what we used).