@scorban2 You cannot lose between those two boats!! I have countless hours of wheel-time in my club's 2700-hour salt water 1998 Ski Nautique, and boy is that a great boat. We replaced the engine at ~2300 hours, so you'll likely be okay with 1400, provided maintenance was good! I really like how those boats drive. I've driven a lot of boats, and those are among my favorite because of their decently smooth ride and good tracking.
I cannot speak specifically about the 1994 MC, but I have spent almost just as much time in the Nautique as I have in my buddy's 1998 MC SportStar (which is just a tweaked 1995-1997 ProStar) as well as a couple private lake days with my other friend's 1996 MC ProStar 190. Those are great boats too. They ride a little more harsh, but that 1996 ProStar especially skis so nice. That PS and the Nautique ski just as nice as eachother, and I think the PS tracks well too. And that 1994 supposedly even has a softer wake than the 1996...
Both are very well-built boats and you'll be in a great spot with either! Pick between the two based off of price, and maintenance. I wouldn't let speed control be a deciding factor.