Which boat has the reputation of being the most reliable and easy to
maintain?

Aluminum rowboat. (just kidding)

Tough question!

Might be hard to come up with an absolute answer, but most boaters hope that
the next boat they plan to buy (regardless of brand name) will prove more
reliable and easier to maintain than the one they own now. :-)

No boat manufacturer builds a proprietary engine. Your propulsion system is the
portion of the boat most likely to create problems if it should prove
"unreliable", and
second only to cosmetic washing, waxing,
polishing, etc will consume the greatest amount of time to maintain.

You might expand your question to what types of engines and drives are the most
reliable and easiest to maintain, and even then you will get any number of well
informed but contrasting opinions.