The DT466 is every bit as good as a Cummins 5.9 or 8.3 at the end of the day. I will say that International motors lost some points with me on the computerized versions of their engines, which that is. A 5.9 cummins cant be inframed, but a DT466 can. Im an International guy but, I think the mechanical 8.3 Cummins is one of the best motors built for large school buses. Now, if you have the 250hp version of the mechanical DT466 in a 9-12 window bus, I'd probably have to opt for the DT for the size, weight, and fuel savings.
That automatic is probably an Allison and you really can't go too wrong. Of course a stick has advantages, but an auto is definitely nice sometimes. Stick shift buses are quite rare in a lot of the country. At that mileage whatever is in there should have a lot left to give. Hopefully its a unit with overdrive(s) and a lockup converter. If it is, that would be a big selling point for me.
I like the Amtrans I know from the mid 90's and the two we currently own are really solid buses. They have under belly storage and air suspensions. They ride great and have above average headroom. The steel seems good enough to me
What's the asking price? I'd say 6,000 retail maybe depending on the tires---could go up or down a lot on that.