While not 100% happy with Finecast, I had the following experience at a local tournament over the weekend which is a major part of the reason I like the stuff:
My Zoanthrope Brood ended up near the edge of the table, and then due to careless elbow placement, one took a tumble off the table and on to my foot. I would rather not like to have discovered what a solid pewter Zoie would have felt like with only a sneaker and sock for protection (probably nothing major, but still).
My Zoanthropes are also sitting on short flying stands as opposed to the tentacle-in-base they come with. Again, I could do that with pewter, but it's much easier to cut into Finecast. I prefer being able to customize my models if the whim strikes me, and options are very limited in pewter.