We have had 9 Masseys now and have not had a single issue with the AC, hardly a big sized sample though. I don't think it has as much capacity as the MX Maxxum or the 40 series Fords though.

If you are open to different brands then you can make an informed decision on what machine to buy and it will be the right one. They all go wrong, even tractors with yellow wheels, it's how the problem is dealt with that matters. Agco get some abuse on here, but we get very good service from our dealer and they are a no brainer for new machines.

As far as the actual performance of the machine goes, as an operator, the only thing I can pull them up on is that in the cab some of the buttons look and feel the same so you (well I do anyway) have to physically look at them to make sure you press the right one.

Our first 8600 had a few issues, but it was one of the first built. It went back to the factory for, err, something, mainly because we had more hous on ours than anyone else. The new one just works as far as I know, so what more can you ask? Really pleased with "my" 7618.

Nebraska tractor test shows both tractors at roughly 25K lb.  Deere doesn't have ILS, but has duals.  MF has singles all around.  I'd say the MF stats you have are for a tractor on singles.

Our 8680 was bought for doing the cultivation work, that is all it did and the 8690 took over from it and does the same work

This tool is the reason we have such a big tractor, it needs to be boss of it to work properly. It will fully load the tractor though it has been on the 8480 it is pretty much pulled as fast as it will have it.

This tool makes it bark too. The 7250 couldn't manage the discs as well. The actual tractor in the photo was of the UK demo machine. Our original 8680 had some software problems, so Agco gave us the demo tractor while they rewrote some software and told us to keep the tractor untill we were happy that ours was 100% as we wanted it. You cannot complain about that.

The new 8690 has had a sensor related to emmisions fail and put it into limp mode at the weekend iirc. The dealer lent us a tracked Challenger while they got the sensor delivered. My 7618 has a sensor fail (probably the same one) but it wasn't working hard enough to put it into limp. What ever emmission system you opt for you will get issues of some sort. We get the odd stupid sensor and I understand people with yellow wheels get EGR valves, DPF regen issues and variable geometrey turbo issues, so you pays you money and takes your choice.

From what I could tell the original 8600 had a load of updates done while we had it and again when it was traded before it was sold on and the new one which is about 18 months old seems better.

To get things straight, I am not the manager, I am what you call a "hired hand" but I take a big interest in the farm

When the 8680 was up for replacement The Management was very keen to have a Challenger. (here in the UK and most of Europe the only Challenger you see are on tracks, Massey is a very strong brand, even after they buggered it all up in the 1990s). So the dealer was called and a new 765 (would that be a D?) came out on demo. The Patriot (green thing on the Massey in the pictures) was taken off the Massey and hooked to the Challenger and she was put to work.

I didn't drive it, not my department, but I am told that it could pull the machine not faster used the same (more iirc) amount of fuel but it did slip less as you would expect.

The big problem with it was how uncomfortable it was compared to the Massey. The red one just glides over the bumps where as everything in the Challenger shuck and rattled, including the operator. The Management came for a drive and decided that he could expect the operator, who is over retirement age and doesn't need the money, to drive such an uncomfortable machine. So after a morning it was parked up, the Massey put back to work and a new 8600 was ordered. I think another nail in the Challengers coffin was going back to a powershift, it always sounded from the outside that it was in the wrong gear, the Massey's engine note never changes. It wasn't quite a straight forward swap anyway, we have a fully mounted in furrow plough that wouldn't work on tracks, but that is not an insurmountable problem if the tractor was going to work for us.

The tracked machine they lent us while the 8690 was down was a trade in with about 7500 hours on it that ended up going to Poland

The demo tractor was new. 

The man that operates that tractor used to own the cultivation tractor but now just drives it because he just didn't need the hassle in retirement. He also had cancer treatment and the banging around in the cab would have been too much for him. He is a very good man and needs a decent ride. 

Demo tractor, it was a C then... anyway, it was new at the time. Must have been 2011

Beautiful.