Hi there,
this may not be directly relevant but we bought a Chinese tractor about 8 - 9 years ago. It's a Siromer (I think Shire is basically the same thing, but in green instead of red). It's 20HP and powers my 4 foot flail mower with no problems, except if the grass is seriously long and thick (as in hay) then I take 2 goes at it. We don't have much in the way of steep land though, luckily.
As for Siromer, well it's OK, but really it's only OK and not a patch on something like a Kubota. I've done about 300 hours on it and the only issue I've had is due to dirty diesel (my fault). I've now changed the stupid filter bowl arrangement with a fuel filter from an old Transit and that has made cleaning out the fuel tank much easier (No need to drain the entire tank to sort out the filter).
If I knew a lot more about tractors then I would have looked around for a British / Japanese make. but since I could have bought a clapped out pile of quality junk that way, I decided to go for new and get the Siromer. My advice would be (based on my experience) get a good make but take someone with you who knows about tractors, then you should hopefully get a good 'un. Also I think I should have gone for something around 30 - 35HP, but that's too late now. My Siromer does what I want but only just, and although it hasn't let me down really, I can't help feeling the build quality just isn't there. However if you want a machine that will build muscles in your left leg then the clutch pedal on the Siromer makes it ideal !!
Keith