Bought the Bart Raven myself as I wanted the Halloween set but wish I hadn't, it's a useless as the burns monster and thanksgiving balloons, won't be buying them either!
Mystery boxes and a Homer Buddhas's are generally accepted as things to avoid using donuts for as they can and very often do just give you items you can use in game cash to obtain. Also if you play daily you get a MB every 5 days so I see no point in using donuts on them anyway.
Best I got out of a MB was the SVT in one game and a lemon tree in the other but apart from that just low cost decorations. Would get an MB or Homer Buddha if you were at least guaranteed to get something worth the cost, a sort of no loss situation and you don't feel cheated!