My experience is just the opposite. I also started with a Sinar F, sold it and bought a nice Zone VI (both 4x5) I give the advantage to the Zone VI for being compact (easy to get in the back pack with other gear), but every other comparison I'd give to the Sinar.
Is the difference enough to make me go back to the Sinar, no....but now having hindsight I would have stayed with the Sinar because there isn't enough of an advantage with the folder to have gone through the trouble of selling all the Sinar pieces and buying a folder....and the Zone VI was more expensive to boot. I use a back pack, with extra pouches attached, and don't mind the weight.
Everyone shoots differently, so YMMV.
Mike