British English has many fond words for a product with flaws.
It has character: It is odd or imperfect in a way that people like.
Temperamental: Of a machine, working well on some days and not on others.
Foibles: Small odd habits or weaknesses, usually forgiven.
There’s a knack to it: It works, but only for someone who knows its trick.
The old girl: A fond name for an old car, boat or machine.