I'd take Conacher. It's a lot closer than you'd think, but I really like Conacher with Stamkos and on that PP.
Both players are being given oodles of ice time, both will be good for years to come.
It's close but I still like CC
2012-2013 Keeper League Champion
Keeper League: Drop four players after each year
G A P +/- PIM PPP GWG W GAA SV% SHO
Centers: Getzlaf, Stamkos, Tavares, Read (C/RW), Grigorenko, Teravainen, Toffoli
Left Wingers: Neal (LW/RW), Ovechkin, Lucic, Clowe (LW/RW), Franzen (LW/RW), Conacher
Right Wingers: Perry, Kessel, Downie, Seguin, Atkinson
Defense: Letang, P.K. Subban, Dion Phaneuf, Byfuglien, Tyson Barrie, Paul Martin
Goalies: Fleury, Smith, Bishop, Rask, Harding, Fasth