Backes went for 5/30, Staal went for 3/10.5, it's hard to compare the two TBH.
I think it's a damn good signing, he can still put the puck in the net and instantly upgrades our center line. Most importantly this allows Granlund and Coyle to stick on the wings, where both are better IMO.
Koivu-Staal-Haula is a nice start for the C depth.
Overall, while Okoposo or Backes would have been nice, their contracts would have been too hefty.