I have a 3 point mixer. I have thought about rigging one of my compact tractors, about the size of your MT180, to run it, but I am not convinced they could handle the load safely. I run it on my IH284, but prefer it on my much bigger IH464. I think I would end up requiring a lot of extra nose weight on the tractor, and would be at risk of damaging things, if the tractor would even lift the full mixer. Mine mixes 6 60 pound bags of pre-mix at a time without spilling; it would hold more were I to set it up to tip upward at a steeper angle. It has a large drum, probably 10 cubic feet or so.
I have mixed feelings about the usefulness of mine. For doing small pours, the setup and cleanup time of the tractor mounted unit isn't worth simply doing the mixing in a wheel barrow. If not mixing more than 15 or so 60 lb bags, the wheel barrow is as fast or faster. For pours over 1.5 yards or so, there is simply too much handling of bags to be very reasonable or enjoyable to me, and I'd rather have it trucked in or brought in some way where I don't have to manually shuffle the entire mass of mix by hand. I buy bagged concrete mix, because it is less work to do that than shoveling aggregate along with handling bags of portland cement.
I don't have one of the electric or gas powered mixers, but have used them, and think that is probably a more versatile option than the tractor mixer, unless you know that your pours will be in locations inconvenient to access with the portable mixer or wheelbarrow. This is the biggest advantage of the tractor mixer, from my perspective: It makes it very easy to mix at a central location and make pours in spots away from hose access or electricity.
