Matt Ryan has always been a quality QB since entering the league but he also has a reputation of choking in big games. This season isn't over so there is still the possibility he could choke yet however he has performed well in his big games to date, including their playoff victory Saturday.
I should add that I'm not making the case for Ryan, I don't really care that much who wins. For me it's between Ryan and one other QB, the one he will play this Sunday for the right to go to the Super Bowl.