Well I ended up getting it in the end. Went for the normal edition since GAME didn't have any of the collector ones in stock. I've seen that you can buy the original Starcraft as a digital download straight from Blizzard so I'll probably give that a shot later on sometime, that was the only thing that interested me in the collectors edition.
I've played it a fair bit so far, something like 10 missions or so. It does seem quite good, just typical RTS type stuff really. Nothing that blows me away but fun enough for a playthrough. The only thing that bugs me at times is the pathfinding of the units, it seems to be atrocious at times, I mean really bad. It's also crashed a few times on me after missions finish but luckily it's got a good autosave that saves just as the mission's finishing rather than at the beginning of the next part so that deals with that.
I can't quite see why it's taken them this long to make a sequel though. The general game mechanics seem to be pretty much standard, the storyline is OK but nothing groundbreaking and the characters are decidedly wooden. I don't find myself feeling for any of them, their interactions between each other are seriously unconvincing. Maybe I'm just spoilt after playing through Mass Effect 2 a couple of weeks ago and seeing what another games company can produce in a fraction of the time. The graphics are also very standard, it doesn't look any better than Command & Conquer 3 from a couple of years ago. I haven't tried it in Windows yet though, it might be better there but I'm not sure if save games transfer over like they do with Steam.