I play both, and going by posts here and in the SHIII forum, so do a lot of people. I never delete any game from my HD unless I need the space (and even then, I'd probably just buy another HD and slap it in), or it ceases to run properly.
SHIII and SHIV are different, but certainly not mutually exclusive. To be honest, I don't even understand this kind of post/question about a game. Especially from someone who has played both, so knows exactly what each has to offer.
As for GWX2, how will you know if you like it and enjoy the experience, unless you load it up and take a boat out on a patrol or two (or many)? Certainly not from anyone's opinion posted here - you'd have to experience it yourself to truly know. And if you really dislike it, a mouse click or two and it's gone again. Nothing ventured, nothing gained (and with nothing to lose but a bit of time, why even pose the question? - just go ahead and see for yourself)
