Greetings….first off, they are both great bikes and products. The only advantage of having the SL would be if you live in an apartment and need to carry it up stairs. The SL really is light, nimble, and relatively fast on the flats. For my riding still, which is mostly paved bike trails and streets, the heavier more powerful Vado is just more fun to ride. The range is likely to be better on the Vado, although I have yet to test it, but the SL could deliver roughly 70 miles in ECO on a full charge. I also have a Trek 8s, and even though it is heavy, I never get tired of the 85nm of torque. For the money, I think you can’t go wrong with the Vado 4. I hope that helps…