My own personal favourite, Papers (papersapp.com), was recently taken over by Springer too. So far, so good--the original team is still running it and there's no sign anything bad will come of it, but I'm still wary of the future.
The Springer-Papers and Elsevier-Mendeley acquisitions are indeed interesting because they've happened at about the same time. It seems that the big publishers want to get a better grip on paper search and/or paper reading habits.
Of course Springer has one of the most onerous paywalls I've come across. I hadn't heard of the Papers acquisition: I use it on my iPad but only because it sucks less than every other solution I've looked at.
What do you think can be done to improve it? Can you tell me what your ideal reference/citation software looks like?