school me on audi a3's

[sixonefive]

so i have always liked audi a3 hatchbacks and have seen a few that are a reasonable price but just wanna learn some more about them before i enquire about one more seriously.

what kind of problems do they normally have?
ive heard bad things about audi electric systems..anything to say about that?
overall driving experience?
would you consider it an upgrade over my bmw e46 325i?

thanks for an info!