I own the Fein Multi-tool and it's a little larger then the one your looking at, I haven't found any use for it on my tanks even with the mini hobby set that comes with it. I use the Proxxon mini sander for hobby use, its small enough to get into tight areas and comes with different shaped sanding heads and three grits of paper that last for a long time. this little sander is used to shape plastics, sands great and I have used it for cleaning up cast metal parts. It's 12 volt (I think it may come in a 120 volt tool also) so you need the transformer, but if you look around you can find a combo set for a good price.
http://shop.sgtooling.com/index.php?...&productId=122
Gary