This car is quite simply the most reliable and efficient vehicle I have ever owned. The first significant problem recorded - besides plastic bits breaking - was an alternator failure at 267000km.
The 1.0L engine was recently freshened up (head rebuilt and new rings/bearings) and amazingly enough only one piston skirt exhibited a tiny scratch - the cylinder bores showed absolutely zero wear. No ridge in the bore after 339,000km is quite amazing considering the mixed city/highway driving the car is subjected to. I attribute this to regular (5000km) oil and filter changes since the car was new. I also use 15-40 diesel oil in the summer (5-30 in winter) for its high detergent characteristics and additive packs and Napa Gold filters - and have since the car was purchased in 1991. I will easily get 600000km on the original pistons/bore if the rust doesn't get the car first. Even if it does, I'll just drop the engine into another body and keep going.
At 120-130km/hr highway cruise the Firefly consistently achieves 57 miles per imperial gallon. I am a long distance commuter and rack up over 50,000km per year so the fuel savings are tremendous.
The car is excellent in winter driving conditions when fitted with good winter tires. It is very nimble in traffic and really fun to drive in any season.
The car is very comfortable with great front seat leg room. I'm 6'4" 210lbs and have room to stretch.
Thieves do not target Fireflys. This is a good thing.
The safety of these mini cars is uncertain. With a Firefly defensive driving is required in a world dominated by SUVs and other land barges. This car is not much bigger than a motorbike and should be driven as such.