There are alot of good things about the ION over the S series:
More head room more leg room
2 rear doors in the QC, new 140hp Ecotec (low maintenance) engine more sound deadening material thicker windshield battery stored in trunk (less heat, easier access, weight distribution) higher stance (no more stepping down into the car) easy change headbulb lamps better headlamp lighting more trunk room electric trunk release center gauge console (aligned with mirrors)
and more... although I am biased towards the old S series, especially the SC, the QC has many nice features. There will be some nice changes for '05 including a new 170 hp engine.
marx404