Which has superior maintenance costs (including time spent getting repaired) and better reliability, ICE or EV? The difference is just the engine right? EVs have less complicated engines, thus need lower maintenance and are more reliable.
Seems almost inevitable; needs a few years to be proven in practice.
I'd imagine the Model S' powertrain will probably be more reliable than one based on an ICE.
With respect to the accessories and interior I suspect Tesla will need some time to come into line with highly reliable brands like Lexus. Since we are early adopters we will surely do our best to help them improve and be patient. :-)
Electronics are not without problems, but OTOH modern ICE has pretty much all the parts EV has including the battery, electric motor, computers etc.. ICE just has this huge lump of moving parts in the engine on top of all that.
Biggest more expensive case to cause maintenance is the battery in BEV. It wears down and will need replacing eventually. It is also the potential reliability issue (bricking), but only for cars that are not maintained properly.
It should be noted, however, that we don't have enough experience. Sure the Model S has less moving parts and stuff, but it also has systems that haven't yet been used in other cars and haven't seen all of the years of varying conditions and use cases.
I feel pretty confident in saying that the cars Tesla will make 30 years from now will be better in part due to things learned about what happens to the Model S as users use and abuse it.
I have read several comments like, "I've driven my Leaf for nearly 2 years and only purchased wiper blades." so I think the EV will be quite a bit less. For now I will stick with getting my Tesla's expensive yearly inspection. After the four years is up I may stop.