Having recently got back into Wing Commander, I pulled out my copy of KS that I never played when I bought it and started playing from the beginning. As far as WC1 and WC2 goes, I don't see/remember any difference between it and the originals. The only glitch that I noticed was on the targeting screen. Occasionally it would target a ship (usually friendly) but it would only show the shields. There was no diagram for the ship itself.
I loaded WC3 to get a peek at it before I finished WC2. Mistake. Because after looking at the graphics on 3, it was hard to go back. I rushed through the remainder of the missions, cheated on some and then just dropped it all together so I could enjoy the glory of WC3. It occurred to me that for a game that is now 10 years old, it looks damn good! 10 years! And WC4 is even better.
Anyway, back to the problems with KS. I have noticed a couple with KS-WC3. While on the carrier, the game has locked up when going to access the main terminal or crashed as some other random areas. It never dropped me during game play. This installation was straight from the CD to my Win XP system. No patches installed. I installed the patch from the download section of CIC for KS and have had no problems since. Granted it has only been a day or so, but it usually crashed on me once a day.
KS gets a thumbs up from me!