As someone looking to purchase a 4310, I am in the same position you are. So... here goes my 2 cents.
Just bacause one user has had problems, I don't feel that the 4310 is necessarly a bad machine. I do, however, feel that it is important to make sure that the machine is used properly, that all 3-pt attachments are properly sized and installed correctly.
As it has been stated earlier, every machine has it's limitations and it is important to realize them before purchase. Considering that I plan on using a 5ft brush hog and a rear finish mower, (as well as some moving of dirt, gravel and hay with the FEL) I feel that the 4310 is sufficient to accomplish everything I throw at it.
(Anyone from Club 4310 feel free to correct me as you already have your machines /forums/images/graemlins/grin.gif and I don't... /forums/images/graemlins/frown.gif).