Shadowrun is one of those games to me, that its system is as much a part of the game as the fluff. It was the third system I ever ran as a GM. One of the only games I never converted to other systems (until now). Because if you were going to play shadowrun and removed it from the system it just didn't feel like shadowrun any more. First edition was the edition I stared with. Second edition came and was used and welcomed it for its changes. While I picked up a lot of third edition books I never played it, It was mostly a reworking of second, expanding and revising it.
But now there is a 4th edition. When I was first introduced to it I really didn't like what I saw. Gone was the die pools and Gone is the weapon damage codes. I felt they just wholesale copied the new world of darkness system for a d6. which I am not a huge fan of. It just didn't have that feel to me that made shadowrun so unique. So my first impression is if im going to play it ill play with 3rd or ill convert it to another system since with 4th I would be doing that any way.
Now after a few months of going over it and playing with the system a little I can appreciate it more now. Dont get me wrong, I see the system in a bit of a different light now. It needs a little house ruling, It has glass ceilings all over the place, and has its quarks. But it seems to work pretty well. The unified system really makes some aspect of the system a lot simpler. But also makes it too simple in some places. Like adding modifiers to a task. Since there is now a set target number for die the only way you can adjust the difficulty of a task is add or subtract the number of die in the pool. Making it the only modifier. This can lead to trouble fast with die pools getting huge since every bonus you get it so the single die pool.
Besides its quarks and short comings I think the new edition is definitely shadowrun. Its fast playing, Most the game system is unified now (I still feel the net is a different system). And most of all its fun.