Once you've tried it I think you'll like it Rob. Both joints are basically tongue and groove joints, the spline is a double groove, free floating tongue joint to be specific. Make sure you work from the same face every time and that way those faces will match. If you are doing something like flooring for example, you would want to work from the rear face so that all the backs would sit flush against the subfloor.
The last thing I would suggest is an offset or oversized base for the router. I sometimes use mine in circumstances like this with my router table plate still attached. The extra wide base will give you the stability you need to keep the slot from dipping and diving if doing handheld.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.