Republicans are upset over the release of Sgt. Bowe Bergdahl in exchange for the release of five Taliban prisoners. They have several complaints: the president "negotiated with terrorists"; the president broke a law requiring 30-day notice before prisoners are transferred out of Guantanamo; and among a few fringe types, a belief that perhaps Bergdahl was actually a deserter not worth rescuing.
Is there anything to any of this? Probably not. But it's pretty much impossible to tell for sure. Republicans these days are so hellbent on finding reasons to be outraged over everything President Obama does, there's no longer any way to tell whether their outrage over any specific incident is real or manufactured. And in this case, it's probably not worth trying to find out.
As a rough rule of thumb, I figure that if there's anything to these Republican complaints, there will be at least one or two Democrats from red states who join in. So far I don't think there have been any, which is probably a good sign that this is just random partisan fulminating, not genuine outrage.
UPDATE: On a historical note, I guess it's worth pointing out that prisoner exchanges—and the issues surrounding them—at the ends of wars have often been contentious, leading to partisan sniping. This is a tiny prisoner exchange, so maybe it's normal that it's leading to a tiny amount of partisan sniping.