I'm with Pistolero on this. Much prefer Madrid to Barcelona. Madrid is a city I keep returning to whereas I can take or leave Barcelona. In my experience Madrid is a far more relaxed and friendly city all round.
I live in Barcelona and absolutely love it.
The thing with Barcelona is the tourist trail is ridiculously localised. The centre is beautiful, but the likes of Gotico for example are pretty much devoid of locals. Also, La Rambla is my least favourite street in the entire city and I avoid it like the plague. Why that is considered one of the "big things" to do in the Barcelona tourist guides is beyond me. But there is a whole city that most tourists don't even begin to see. Every barrio here has a distinct identity and flavour, and even the barrios more towards the outskirts (where I live) are just as lively as anywhere in the centre. And its so easy and cheap to get around - you'll never have to be on a metro more than 20 minutes. It's also a great city to cycle and walk around, and it is also so easy to esacape the city here and head up the coasts on the weekend.
Problem with Madrid is it is much more car dominated, the barrios away from the centre are less distinct and take much longer to get to, the summers regularly reach 40c+, the winters can still be freezing, and it is about as far from the sea as you can get in Spain.
I do agree with Madrid being friendlier though. It also has lovely parks, which we don't have in Barcelona (although with the climate they shouldn't really have them in Madrid either...). Also, it helps that the Madrid tourist sites are scattered across the larger central area which helps decentralise the tourism a bit and gets people to see more of the city.
On the laid back thing, it's a strange one. Madrid is a much bigger city, but I agree it does feel more laid back. I think this is because the roads are wider to accomodate more cars, whereas Barcelona is much more densely populated with many more narrow streets so it often feels busy.
Personally I like them both, but to live in Barcelona would be my only choice.