The good:
Considering 175,000 miles on this little car, I'm impressed with how well it's held together. Performance has not suffered one bit since the day I bought it.
No repair I've done to it has exceeded the cost of having the timing belt done, which is routine maintenance anyhow. I've only been stranded twice with the Storm in around 50K miles; once when the timing belt broke, and once running out of gas. :P
The Isuzu engine runs strong with no leaks; for its size, it is zippy for getting around town. It gets anywhere between 24-33mpg depending on how tweaked the driver is. :) (To get decent performance/mileage from this car, it helps when the driver has driven it long enough to "know" the pedal, e.g. when it needs more gas, when more gas isn't going to help, etc.)
Running the A/C bogs it down quite a bit though.
My engine has a bit of blow-by from high mileage, but nothing to be concerned about (will use 1qt in approx. 400 miles).
The 3-speed automatic leaves wanting for some more high-end torque, but the shift points are logical and getting up to 45mph is fast enough. The transmission has not exhibited any problems yet; I have cleaned out the pan and re-gasketed it once since owning it, and I drain and refill the fluid yearly.
Sporty and unique look; doesn't look like the typical American bargain-box.
The bad:
Since the car is very low to the ground, it eats exhaust parts and CV joints.
There are known problems with the ECU that I have not encountered yet, relating to idle speed fluctuation.
The exhaust manifold is also a known problem, but any aftermarket manifold should be designed to prevent cracking in the OEM manifold's weak area.
The last widespread problem that I know of is that the throttle body and idle control actuator will become caked with carbon after so many miles, causing decrease in performance and some idle problems. Spraying carb cleaner into the throttle and on the IAC motor's spindle clears the problem up.
The car is small, which helps make it a good utilitarian car, but it's a pain not having usable back seats. The hatchback makes up for it though.
Summary:
The Storm is a reliable, economical, and almost sporty car that will go the distance very cheaply if you have the knowledge to make minor repairs to it.