Steve
I have basically the same saw. Mine was purchased in the early to mid 90's. When I upgraded to a nicer saw, I had the same basic questions that you are having.
In the end I kept the saw, and I have always been glad I did. It acts as an outfeed table for my other saw, and I still use for crosscuts, when the other saw is setup for rips. I also use it to cut pressure treated wood, lexan, plastic and aluminum, materials I do not want to put through my other saw. I've also moved it outside when I was doing some renovating on my porch.
In the end it is up to you, but having a "junker" saw for nasty work, really isn't that bad of position. My lift mechanism was also messed up, until I took the whole thing apart and realigned it. I used to just take the blade off when not in use and not mess with the raise mechanism.
"The first thing you need to know, will likely be the last thing you learn." (Unknown)