It brings in several interesting tactics. Technomancers and Hackers play almost like mages now, since there's usually something around that they can wirelessly affect, in one way or another. A hacker driving a car through his 'link, for example, can real-time hack gridguide at the same time to cut his travel time. 'Course, it takes a really good hacker to do that and not get caught...
I've run quite a few games now with sr4, and I find the system to be a good one. It brings the whole game together, with all mechanics working the same. I've acquired and tested the mechanics and spells coming out of Street Magic, and even played around with a few initiate mages as NPC's. For the most part, SR4 seems the superior system.
I like it mainly because it allows a lot more player survivablility. For instance: Dodging, this used to require dice left over from your combat pool (and who ever remembered to do that before their 9th character). With the new combat system, hitting anything is an opposed test between your skill+attribute and the opponents reaction. Plus dodge or gymnastics if they decide to go on full defense. This makes for a smidgen more character survivablility. Before anyone pales in shock, remember that it takes a lot more successes now to fully dodge an attack, sr3 might let you squeak by with 2 or 3 sucesses to dodge a pistol shot, that also might only have had 2 or 3 successes. Sr4 ups the stakes.
Another thing this system offers, is a built-in mechanic to allow new players to catch up to the learning curve, as far as what they should and shouldn't decide to engage. If a character dies, he can permanently burn an edge point to "survive against the odds." In this case, he'll wake up in a hospital, or perhaps get picked up by his team, or, if I'm feeling mean... wake up in the middle of the barrens with a screwed up condition monitor. But the point is, this character is ALIVE. I don't have to mess around with having the player make a new character (greuling in sr3, and still not too much fun in sr4), or changing the name and re-introducing himself with the same stats. This mechanic, and other things invilving edge, pretty much sum up what I love about the new system. Edge replaces uber-confusing dice pools, and is generally more useful. Wiley, my advice to you, when you're making characters, is to make sure they have high edge attributes. It may seem like a waste of points at character creation, but it'll pay off later.