One of my friends, his dad has a 330i auto with nav. Its really boring. It's difficult to express just how dull it is, even the owner regrets getting it. Its an odd drive as well, usually in an auto, kick down occurs when you floor it. In this car you have to lift and then floor it otherwise it stays in the same gear and plods along. The interior is bland, however the nav is good as is the sensor for parking, you get a radar style visualisation. Its certainly fast enough and holds the road like its glued.
I've driven the is250 and found that to be a better drive. Its well built, comfortable and fast enough for uk roads. It might not be bmw fast but thats the choice you have to make.