I finally got around to starting this properly this weekend, and ended up pumping around 5-6 hours into it. I was hooked!
I had a few performance issues at first, which seems to be common unfortunately. I've on a pretty hefty laptop (680m 4gb, with 16gb RAM, and an i7 processor) so it was a bit of a shame to have to drop all the settings a bit. It still looks good though.
It's so nice to play a game where your hand isn't being held all the time, you're just free to do what you want, work out what is best to do, and then do things how you want to do them. I know there are set ways to complete certain missions, but there's usually quite a lot of them, and it's not always obvious. I really like that.
I checked a walkthrough to see how far into the game I was, and it looks like I'm only about 25% through the missions, so it'll probably be about 20 hours for me to complete this! Great value!
Controls are great as well!