They are definately good tractors.  You will either love belts or hate them, I think it must depend on how you were brought up or genetics or something unpredictible like that. 

The 'better ride' part is 100% dependant on the conditions you are operating in.   Tracks can be 100% better then tires or 50% worse in different situations.   

Since I own a tracked tractor I guess I can answer.....

Tracks do not like any situation where you have to run over any thing the raise above the surface.   Tracks are like a bull dozer in that they have the teeter totter effect.  The under carriage is ridged (straight).  If you go up a rise then it starts to fall off on the other side, the tracks do not start down until 50% of the vehicle weight crosses the peak of the rise.  Then the teeter totter flips and the tracks slam down on the other side.  Terraces are terrible on tracks.  Now  a depression is just the opposite.  Tracks never fall in the low place.  They just go right over it.  If the ground is moist and has some "give" to it track ride very well.  But in drought when the ground is very hard, tracks can have a lot of "vibration".

You can turn and run perpendicular to the rows with a track tractor and it can be as smooth as glass and the wheeled implement behind you will be being beat to death.  But lay a 4 x 4 down and run over it and tracks will throw you thru the glass.

The others have pointed out one thing.   Another which we have found is certain situations where the ground is worked up very loose.   I hate running the Cat's on fields which have been disked deep.  All day long you are climbing up on top of the loose dirt.  You climb up until you get more weight up then the soft surface can support, then you sink back in again and the process starts over.   It's like being in a boat on a rough lake.   The same conditions in our 4wd are usually reasonably smooth, although I have seen occasions where they behave similarly.  Add slight ridges from the disk makes it even worse.    The best answer is to not use the stinking disk. 

On the other hand, go into a field with old rows, or a field which has been chisel plowed without a harrow, or any similar corrogated surface and the tracks can run at any angle other then a very shallow one and you won't even notice them.  You will be able to find a "bad" angle if you try, but it is fairly specific...90 degrees to the rows is fine, somewhere around 5 degrees  probably not..   A tire tractor couldn't even think about running 7 mph at 90 degrees to old corn rows. 

The one place where I have found that a depression will cause a problem is if a wash is in enough of a Vee that the front roller hits the other side like it was a raised place. Running the grain buggy over a wash comes to mind. If the wash is pretty flat no problem but if it is vee'd down look out. Going at an angle helps but sometimes not possible with grain buggy while under combine.

Like Don said, in hard ground conditions sometimes they can vibrate quite a bit.

Tracks, like about everything, have tradeoff's. Some guys like them, some don't. We run 3 track tractors (JD8300T, JD9400T and CH45) and several tire and my operators have pretty well indicated to me at trade time it wouldn't hurt their feelings any if the track machines left before the the tire machines. They all seem to like the CH45 on the grain buggy - that is the main exception.

It is definitely an operator preference thing because i don't care much for the tracks on the grain buggy and everybody else does yet I kind of like the track machines in the field and everybody else would just as soon hook up the tire machines. Best riding/operating/pulling machine we have is the JD9400 with tripple 18.4x46's. Used to have power hop problems till we finally got it weighted down enough. I don't personally see where the 9400T has anything over it at least for what we use them for.

Everybody hates them going down the road - and we have a lot of roading to do. In our area we farm with big tractors in small fields because our window of opportunity is often short. We justify the big tractors by having three distinct seasons when we can run them. This makes for a lot of changing fields and we can be on the road sometimes three or more times per day. I think that is one of the main reasons the tracks are not very popular in our operation.

They ride the very best they ever will when they are brand new and go downhill from there. On a new tractor the rubber has not work hardened so is softer and the lugh are deeper. We had two CH45's for a while that were identical except the one had 32" belts at 80% and the other had 24" belts at 20%. You would have thought they were different tractors. The one with the worn out lugs would actually vibrate enough on gravel washboards it would vibrate sideways towards the ditch when the road was sloped quite a bit. Don't underestimate how much poorer the ride on a track machine is when the lugs get about half worn out. Sure seems hard on the cabs going down the road.

This is the stuff the guys of the track religion fail to mention. They are good tractors and pull really well going straight and in a lot of conditions ride very well but they do have some disadvantages.

John 

ride quality of the Cat large frame and MT series track tractor by comparing them to what JD has marketed, you will come up with an inaccurate picture.

Lots of places to soak up shocks in the suspension of my 75 and MT that just flat don't exist on the green track machines.

I would not argue with you about the new Challengers riding better although I have never driven one. It looks like they ought to. If I ever own another big horsepower Challenger it would be the new 4wd. I just haven't seen any great big benefits to tracks in OUR operation. The only reason we own three of them is at the time of purchase we bought them right. Two were used and the other a 200 hr 3 year old demonstrator.

John