One difference
One big difference between the Gruv and the Rans geometries, is that the Rans retains the same geometry as the seat is raised. With its more upright seatpost, the Gruv changes as it goes up. We own both the Gruv 2.0 and the Rans Fusion. You definitely reach further forward for the bars on the Gruv. The Gruv has 24 speed rapid fire type shifters the Rans has 27 speed Sram twist shifters. The Rans is WAY lighter and more performance oriented. I am a stronger rider than my wife, but when I am on the Gruv, I have a hard time keeping up with her on the Rans. The Gruv is easier to stand and pedal on. With the way the BB is positioned in relationship to the handlebars, when you stand on the Gruv, it feels more like a standard bike (except you lose traction easier). I use the Gruv as a MTB quite a bit. I put a MTB crank on it and some aggressive tires. It does a decent job.