I play PZC, WWIE and a bit of HPS Napoleonics. I think HPS games are by far the best PC wargames on the market. They strike a great balance between playability and realism.
My only gripe is that some (not too many) of the CG's are unbalanced. As I only play CG's this is sometimes a problem. I wish the people who do all the mods would put some effort into play balance rather than just tweaking unit values, which sometimes just makes the play balance even worse. Which is why I generally stick to stock games.
But overall a great system and 'bug free' which is a big plus. Not to mention the efforts of Glenn. Only recently he saved a CG of Stalingrad for me from being ruined by a flawed release.
A bug thanks to the HPS team and Glenn.