[citation][nom]classzero[/nom]It's blizzard, I learned my lesson with Diablo III and SimCity(EA). I will not buy zero day release titles.[/citation]
Expect that HotS is an expansion with already established infrastructure. The only issue there was, was achievements being down for like an hour which slowed my brutal campaign progression just a bit since I didn't wanna replay those few missions to get the completion achievement.
That said, it took me roughly 10 hours of gameplay (on brutal which plays at 150% speed, but it also features heavily upgraded opponents which evens things out).
Cinematics are effing brilliant and there's a competitive and non-competitive multiplayer component with some new and some changed units. Well worth the €30 I paid for it.
If you're interested in getting it for less than on Battle.net, google 'allkeyshop'.