That's interesting, I haven't had those sorts of problems with finecast. It certainly doesn't bend as much as metal or plastic, but I found it bends enough so that the models don't get damaged. One tricky thing with finecast is when you're bending it, it doesn't give you any warning that it's about to snap, where plastic and metal I tend to be able to bend them right to the limit of snapping, finecast you'll be bending it and then all of a sudden with very little warning it'll just break. Because of that, if I want to intentionally bend finecast I'll always do it when the model is warmed up and more supple. One of the guys at my hobby shop proved just how much it can bend by reposing a Hive Tyrant purely by bending it (all while the model was heated up).
With the paint sticking to the model, that's weird, do you prime your models? With spray or by hand? I've personally found finecast to be very adhesive to paint, where plastic has a very low surface energy so paint tends to bead off it, and metal is, well, metal, so paint chips easily, I've found paint spreads really easily over finecast even when it's bare (though I typically spray prime all my models anyway) and haven't had any issues with scratching or chipping (but that said, I'm very careful with all my minis be they plastic, metal or resin, I'm always careful to make sure that aren't handled in a way which would result in chipping).
But yeah, casting flaws have been my main hatred of finecast. Maybe I should start mail ordering it, coz all the stuff in my local games shop has lots of bubbles which you can see even before you open it. It's stopped me buying Arjac Rockfist or any Tyrant Guard, I couldn't actually find any in the shop that didn't have casting flaws that I'm too lazy to fix.