I was thinking about buying this game and i just wanted to ask if it's any good?

That depends largely on what you like.
If you're into many spread sheets, data collecting/comparison, managing firms simultaneously if needed and a virtual business world in general, there's no better.
However, it can be rather boring for not-so-hardcore players.

If you're not sure, there's a demo available. You could give that a try. You may have to fiddle with it to get it to work on a modern system.

It's very good. It might not be everyone's cup of tea, but once you get into it, you'll probably find it very addictive. Every couple of years, I start playing and get totally hooked on it for a few weeks. Despite the very old-fashioned presentation I don't really think the gameplay has aged a lot (somewhat due to the fact that it was a very unique game to begin with, and it still is).

So I say go for it. I think I posted a bunch of hints and tips in another thread last year (shouldn't be that hard to find, this subforum isn't exactly busy), which might be helpful.

Edit: http://www.gog.com/en/forum/capitalism_series/anyone_playing_cap_plus/page1

wheres the demo?
and thanks guys for all the advice i'm buying the game soon