A Bose-Einstein condensate is used as an atomic source for a high precision sensor. A 5×106 atom F=1 spinor condensate of 87Rb is released into free fall for up to 750 ms and probed with a T=130 ms Mach-Zehnder atom interferometer based on Bragg transitions. The Bragg interferometer simultaneously addresses the three magnetic states |mf=1,0,−1⟩, facilitating a simultaneous measurement of the acceleration due to gravity with a 1000 run precision of Δg/g=1.45×10−9 and the magnetic field gradient to a precision of 120 pT/m.