I watch far more of Real than I do Barca (simply because I'm a big fan of Benzema, Cristiano, Alonso and Kaka). Although I enjoy watching them, my biggest gripe with them is that they seem to be a team that is overly reliant on individual brilliance. I have not looked at their assist stats, but I wouldn't be surprised if as a team they had far fewer assists than Barca despite having far more goals. The issue is that a lot of Real's attacking is individual based - almost like an NBA clear-out offense where Kobe or Jordan just dribbles past 4 defenders while the others watch.
This type of attack, I feel is less likely to succeed against barca because they can simply swarm the attacker with the ball and regain possession. It leaves you in danger of losing possession frequently while on attack, and putting you on the back foot.
The only team that I would trust to consistently go toe-to-toe with Barca would be an Arsene Wenger coached team that has quality attacking midfielders.