Pros
The only "pro" of working at Springer is that the company is so woefully disorganized that you can get away with doing any real work. It's the kind of place where your manager is either too incompetent or too checked out to care whether or not you disappear for a few hours. No one is running the ship, therefore, no one cares where it is heading.
Cons
Springer is among the most demoralizing workplaces I've ever been in. The company is constantly changing everything about its business practices, rolling out programs before critical errors are resolved, and reshuffling employees. The addition of Nature Publishing Group is only going to make matters worse, as Palgrave and Nature are just as poorly managed (though both companies are under the impression that Springer is a bastion of organization).
