It all depends?
The biggest thing is, how the original owner(s) maintained it?
If they took care of it and drove it, shoud be ok. If it was a garage queen (80k is not a lot of miles for an 86), then you're likely going to be putting some $$$ into it in the form of hoses, wiring, and miscl. parts that deteriorate.
Pros:
1-(Depending on the price) no car payments.
2-Old school vette body. No mistaking the C4 for anything else
3-Relatively cheap to keep and gets decent fuel economy.
4-Better "feel" according to some. It wraps itself around you when you enter.
Cons:
1-It wraps itself around you when you enter
More difficult to enter and exit than a C5 or C6.
2-Old school car. The $$ you save with the lack of payments might end up being spent on service and repairs.
3-Rougher ride. Not as civilized as the C5/6's. more "in touch" with the road according to most peoples comments.
5-More difficult to find parts and, being the bastard stepchild of the Corvette community, no one wants to make aftermarket or custom parts for them
The C4 can be a blast
They're good looking cars, but again, they're 20+ years old. they have squeaks, they tend to leak (a little to a lot), are rougher riding and less civilized. They can be made STRONG by building on the basic engine or transplanting an LS motor as many have.
I have an 87 (for sale) that runs like a charm, doesn't give me problems, and is dependable.
Since it's paid for, if I wanted to mod it, I wouldn't have to worry about voiding warranties, or screwing up an expensive car.
It all depends on what you want?