Well!
Basically last years 7000 series was a huge step forward for Cub. It was the first time (in mine and other dealers opinion) that Cub made a crediable entry into the compact market. It had the right gear, a great 4wd system, good flow capacity, lift capacity, attractive design, and an ergonomical operators station. It wasn't without its flaws however. The main problem was that when the tractor was outfitted with a FEL that aditional weight combined with the weight of the CAT Diesel caused serious front end problems...even a few broken axles.
There we of course other small issues that had to be worked out (as with any new model no matter what the make, look at Kubotas RVT). The new 6000 series has all the great equipmentt the 7000 series had with a much improved front end, mainly due to a much stronger housing and axle shafts as well as a new loader design.
The CAT diesel and the 4wd system work great together...PLENTY of low end torque.
There are of course still things Cub needs to work on. They still haven't found a way to fit the actual hydrostatic unit into the trans. casing...in other words since it is external (not sticking out of the tractor, just not in the tranny case) the units "whine" is much more noticable. This means nothing, but to unknowing customers this will surely raise questions about quality.
The 5000 units are OK, but they are nothing more than overgrown lawn mowers, just like the BX series. The 6000 in my humble opinion would be the best of both worlds and it shows Cub's committement to trying to get a foothold in the compact market. Another big problem for Cub is engine manufacture. They have yet to ink a big time deal with a diesel engine manufacturer...something they are going to have to address in the near future. It if is CAT thats great...but issues about servicing CAT motors has arrose...plus they are like buying John Deere, paying a lot for the name. But I am sure I am boring you by now...good luck!