I absolutely loved this game! I'm so glad that it's on steam now, since my old disk has been getting fairly scratched up over the years and it's nice to have a reliable copy.
While the game's graphics have probably not aged very well for those not viewing it through nostalgia-tinted lens, it actually stands up fairly well still (native 1080p, anyone?). The strategy side is still rock solid as well, and it's implementation of formations and terrain remain uniquely excellent in my opinion. I know the old version had some stability issues, but I believe those have been addressed as of now.
The single player story is definitely the selling point for this entry and I absolutely loved it's branching endings. No matter how many times I play it, every year or two I find myself putting it back in and booting it up to play through again! The multiplayer is kinda meh in this entry, but it's still serviceable if you'd only like to buy one out of the two. So for its excellent strategy, epic story and strong replayability, I couldn't recommend this game more highly! Buy it already!