I know that this not the answer you are looking for as I don't have a 750. I had it's bigger brother the 1050 until about 2 months ago after 15 years of loyal service. It was a very good tractor, the Yanmar was tough as nails and started in the cold very well. Parts were still available, although I never had to get many. Check on JD Parts on-line. I had a loader on it and arear blade for snow removal, although a bit light sometimes, it always got the job done. Mind you I am up in the North where the snow isn't very heavy. A snowblower would probably be good on it. Hopefully you can get some replies from a 750 owner.
I don't have a 750 either but I do have a 950. Again, a big brother.
Jake is right. Parts are available with no problems. http://www.jdparts.com will let you look at the all the parts diagrams and if you have an account, you can order an parts that you may need and either have them shipped to your dealer or to your home.
I have operated a 750 a number of years ago. It was just as tough as my 950 besides the obvious smaller stature and lower weight. The horsepower differences are not that large either.
I ran the 750 with a 4ft. brush hog with no problems at all. I feel pretty confident that it would run a 5ft. grooming mower, but definately a 4ft. grooming mower. Sorry, I can't comment on the snowblower though, I've never been around one.
If I didn't have the 950 and a 750 presented itself at a really good price, I would jump all over it. Power steering is not a necessity unless you are running a loader. With 4wd, it is unstoppable. The Yanmar diesel just sips the fuel as well.
Hope that helps a little. If you have any specific questions, please feel free to ask.
I had a 650 that I used for 15 years. As the others have said- parts are no problem to find and the motor is great. I ran a bush hog (4 ft), box scaper, 6 ft mid-mount mower and never had any problems. If the 750 has 4x4 even better- you'll love it.
Just got a 750, buddy has had a 650 for years and says the engines go forever and highly recommends them.... His had 67 loader, better suited on 750, so its going on mine... hydraulics switched right over, with some patience..