No automobile is maintenance free, even bicycles need maintenance.
If you are talking about maintenance friendliness, I think 400E should be first ruled out. In my ownership experience of serveral cars&trucks, 400E is by far the most difficult one to work on by DIYers, especially anything under the hood, how about spending 6 hours in flushing cooling system, and 6 hours in removing camshaft cover and failed?
99 BMW 540i 6-speed 110K Km
03 SAAB 9-5 wagon 80K Km
92 400E (Sold) 245K km
Still missing the days with the Benz, it kept me busy.