Well, I've put a good few hours into Metal Gear Solid 4: Guns of the Patriots now and have completed the first act (an act which causes the game to spend three minutes installing more game to my hard drive. Didn't I get a console to avoid all this?).
I approach this review from the perspective of a relative newcomer to the Metal Gear series. I played and completed Metal Gear Solid on the Playstation years back - I thoroughly enjoyed it but found the experience short lived. I'm well aware that from other comments I've read on the web that this one in the series is really dedicated to the fans; There seems to be a phonomenal amount of backstory to these characters that I'm not aware of and even reading 'story so far' posts on wikipedia only satisfies my curiosity about the Metal Gear Solid universe to a certain level.
The game itself? It's a sequence of absolutely gorgeous cutscenes interspersed with the occasional bit of game. Enemy A.I. hasn't moved on a great deal from MGS on the Playstation. Enemies see you, so you hide. After a short period of time they forget you ever existed and carry on as they were. I may be rubbish at it but MGS4 seems to be a lot less about stealth and a lot more about gunfights - the first perspective person mode works very well for this.
Probably the most damning thing I can say is this; With GTA IV I actively looked forward to playing it and completing it - even though I've beaten the actual story mode, I'm still keen to explore every nuance to a fine minutae of detail. I'm in no doubt I'll complete Metal Gear Solid 4 but I'm not actively looking forward to my next session on it. I'll beat it through a sense of getting my monies worth and to see how the story pans out rather than to play it for the sheer enjoyment of it all.
I am very aware that this is a game that may suddenly grab me.. In which case consider this review a work in progress as opposed to the finished article. Time will tell.
Incidentally, this is the first blog entry I have ever made from my mobile phone.. An n95 8gb by the way. Sitting in the merchants pub in rugby drinking a pint of white dwarf. Best phone I have ever had. Hark at david dragged kicking and screaming into the twenty first century.