Navigation is easily controlled with the iDrive knob. Previous destinations are sorted in reverse chronological order. New destinations are easy to enter. Adding destinations works as expected (insert/append). When the fuel gauge reaches 1/8 of a tank the car prompts to add a gas station on the route which can be accepted with a single button press of the main iDrive knob. When a trip is in progress I can search on the route by category for points of interest like rest stops. It picks up traffic information over AM radio and uses that information when routing.
Similarly pleasant experience when operating the radio/built in mp3 player. Everything can be done with iDrive but there are also dedicated buttons on the steering wheel and dashboard.
Climate control is managed by physical knobs.
Bluetooth calling is supported but Bluetooth audio (music) is not.
Overall an excellent experience. It's obviously dated and a little slow but completely serviceable even today. The system is completely self-contained so it does need map updates from time to time. OTA updates, even on wifi would be nice.
From a design perspective I have no complaints at all, it is well integrated with the car and otherwise stays out of the way. A helpful tool.