Those early LT1 optisparks were problematic, the later ones were definitely better but that is a relative statement. Even if you have a good one, if the water pump goes, and it will, you no longer have a good one. Luckily I never had a problem with my opti, which is good because they are pricey, many of the aftermarket ones are of questionable quality, and its a good bit of surgery to get to.
About eight years ago I paid $1000 more for my '96 that had fewer miles than this one. But he was unemployed and desperate and I took advantage of that. This one looks like its in super shape. The price is probably about right. But it still has an optispark....
I would never talk anyone out of a C4, I can only give my experience of what mine was like. Fairly reliable, though it did nickle and dime a bit at times. EGR valve, temperature sensor, fuel pump, tie rods, rotors, rear wheel bearings, power seat motor... all before it had 50,000 miles. None of which was difficult to get locally, none of it difficult to replace, and none of it was expensive at all, however tires for the beast were NOT cheap.
Drove fairly nice. Tramlined over every little crack in the pavement, which I found annoying but got used to. With the glass top removed the body wiggled and jiggled over bumps like a wet noddle. Didnt handle as well as I expected it to. Average brakes. The glass top also let an annoying amount of sunlight and heat in on hot days. Was not easy to get in and out of.
Nice exhaust rumble. Gobs of torque. Nice interior layout, was very comfortable (once you fell into it... see previous paragraph). Got excellent MPG considering how much power was on tap. Very nice stereo. It was a beauty and it cleaned up very nicely.
Hope this helps. C4's have their fans but if I get Corvette fever again it will be a C5 or newer. I've driven a few and I liked them a lot better.