Citroen 2CV Reliability?

If properly maintained (a cheap and easy task) then they're very reliable.

I've had one as my daily drive for the last 7 years and the only breakdown I've ever had was on the first drive home (the points and timing were off, causing the ignition coil to overheat). Since then I've done over 80000 miles in it without any problems at all. The car still reaches just over 70mph on the flat and will happily go flat out all day. I've driven across France into Spain and Italy in it and driven more than a mile high in the Alps and Pyrenees. It never fails to start whether it's at -10C or at 40C.

The reliability comes from the simplicity: it's air cooled so there's no radiator or water pump to go wrong. There's no distributor, no brake assistance or power steering, no engine management system. There's just two cylinders so the engine has fewer moving parts. It doesn't even have cylinder head gaskets nor a timing chain/belt.

In the past, the cars have been owned by people who bought them cheaply and ran them with skimped maintenance, and those cars certainly did break down or even suffer engine fires resulting from the cardboard heater tubes getting so neglected that they fell onto the exhaust manifold. Now that 2cvs are rising to silly prices owners tend to take better care of their investments. 2cvs can suffer a few electrical gremlins due to Citroen using really low quality bullet connectors throughout the wiring loom, but I've never had one of those cause a breakdown on my car, and the few times they have caused minor problems the fault has been easy to trace and to remedy.

There's also a wide network of owners clubs for the car who liaise with each other to help if breakdowns do occur and spares availability is very good. They also run perfectly well on unleaded fuel.

Combined with the practicality of the design, the fun of driving it, the social scene attached to ownership and it's ability to keep up easily with modern traffic I really cannot see myself wanting anything other than another 2cv or the near mechanically identical Dyane.

Yes, but compared with modern vehicles, they are high maintenance (but if you don't mind doing odd jobs, that is not a big problem). Grease kingpins every 600 miles etc. There are some excellent specialist mechanics who will probably be pleased to show you the basics as they may well have more work than they can easily deal with, and seeing your car once a year every year may well be enough?