Express is the most popular. As a freelancer I always enjoy when I see express as the framework of choice, since it's very easy to maintain the produced code and is very hard to go unmaintainable.
As a matter of fact, what I don't recommend is Sails [1], which tries to do as much as it can and is quite inflexible in terms of technical decisions
As a matter of fact, what I don't recommend is Sails [1], which tries to do as much as it can and is quite inflexible in terms of technical decisions
1 : http://sailsjs.com