I have an 1155 and it works really well. I used one in the 80's when I worked for a local farmer and really liked it. The farmer I worked for as a kid still has his tractor to this day and still uses it. It's never had any major problems.
I purchased my tractor in 2008 and it needed a bunch of work to get it reliable again. It had been sitting for a very long time and this damaged the rings in two cylinders. I didn't pay very much for it when I bought it so I could afford to invest a little. Now that the engine is rebuilt it runs great. I also replaced the three point control valve (under the lift cover). The only other thing that has happened is the flange on the power steering rack broke off where the tie rods connect (this surprised even the dealer). Everything else I have done is cosmetic. They look great if you take the time to restore them and they don't look too dated. Now I get to wear it out.
It doesn't hurt if you have a soft spot for these tractors. It's also good if the local dealer knows something about it. My dealer is very knowledgable and most parts are still easily available.
Lastly, you have to remember that they are 35 to 40 year old tractors. When they get this old, you have to fix a few things – doesn't matter what color it is.