I guess it depends on what you intend to do with it. I don't see any rear lift on the Cub with the rear PTO, and I don't know what implements you could find that would work with the rear PTO or where you'd find them. If you're intention is to sell off the rear PTO then maybe that is a different matter.
The engine on the 1250 is an rubber iso mount engine, and those iso mounts have a limited life. They are also pricey items to replace. If not replaced in time, the aluminum oil pan will wear down against the frame, and you'll have to replace it, too. Make sure the electric PTO works because that is another high dollar item. Another weak spot is usually the muffler box will be all cracked up.
The older Cub engine is easier to get to the air filter and carb for routine service because you don't have the side panels. The 1250 side panels were designed to control noise and to help direct air flow over the engine.
Really, they are two different machines, and you need to be careful to be sure everything works as it should or you can sink some bucks replacing parts. Just be careful to look the 1250 over very carefully for the things I mentioned because they can go unnoticed and set you back some money if not caught.
