There are a few things i look at when purchasing a tractor, or any other piece of machinery. It is good to listen how neighbours have got on with theirs, there has to be a good dealer backup service, (all salesmen can sell tractors), and with the price of fuel nowadays, economy is high up the list.
To a certain extent the man sat in the drivers seat has a lot to do with it, if he hates the machine he will not get the best out of it, (i have been their in my younger days), especially when using it for up to 18 hours a day.
All tractors have their good points, and bad, we have had Ford, MF, Deutz, and Renault, at the moment we are JD for the smaller horsepower and Case for the high, that works for me at the moment.