I’ve had a closer look at the mutron and I believe that the “SWEEP” settings appear to be about the same as the “depth” setting of the ModFactor. Then if you want to control the “sweep” with an expression pedal you will have to set the “SHAPE” to “exp pdl” on the ModFactor. This is basically bypassing the internal modulation source, about the same way as what is done with the Mutron.
You can then certainly use the ModFactor in a similar way as the Mutron. The big question here is that because they have different filters they will not sound exactly the same. This is a matter of personal choice. Then I’m sure you can do much more with the ModFactor because there’s much more ways to modify the sound with it. You will have to judge by yourself and best is to try one and play with it at the store.