I'm a BMW fan, just sold my 2002 325i sport/premium. 530i is an excellent value/jump up. With updated engine (255hp), this is a fun ride. Either love or hate the exterior, interior is well designed. IDrive was no issue for me, if you can navigate an internet web site, you can use IDrive...I highly recommend the Nav system, especially for safety (not having to look around while driving, it tells you when and where to turn). Trunk space is a big step up from 3-series...premium package a must (nice leather). Decided against sport package, since I live in N. PA...snow and ice is not recommended for sport package. Loads of technology in 06 model...enjoy the toys. Love the way it handles.
Nav system, cold WX package (when winter arrives), overall performance, acceleration and handling. 255hp provides excellent acceleration and fuel economy is not a problem... getting 28mpg driving to work averaging 38mph on the drive. On board computer fun to use.
Water pump quit after 300 miles, sat in shop for 5 days, but BMW provided a rental, and their service was excellent considering the situation...had to use BMW roadside assist...they were excellent also. If you have an issue, BMW will fix it for you. Good experience considering...