Too much of the hacking/tailing is just standing around, if you're the attacker. That, and I don't like that it depends heavily on where you spawn. There are some places (neighborhoods, wooded areas) that are GREAT for hacking, but some (open roads, city area) that suck because of the open space and numerous cameras. The race is just kind of a race, nothing special, and when you add the shoddy driving physics, it's a bit underwhelming.
Right now, I'm trying to fly through the side missions and discoveries I didn't do during the campaign. Going to try to trade the game in for $44 at Best Buy this weekend, if I can get it finished.