I'm going to get it but not while it's still fifty quid. The reviews I've read have all said that if you're imaginative and want to explore loads then it'll keep you entertained for a while but if you like to speed through games quickly then the story doesn't last that long.
GTA with a parachute..on a miamiesque Island...not bad at all and good fun firing a grapple onto a passing helicopter ,climbing up and nicking it...then take it up into the clouds for another skydive...