I do not own a Prius yet, but because I like to work on cars as a hobby, I might buy a GEN 1 tomorrow. It has some issues, and this forum seems to hold enough knowledge!
Maybe hold out for a Gen2, they have less mechanical issues and more abundant cheap parts... Lots more repair info on here for Gen 2 too.
I liked my Gen 1 and I miss it. But they did make a number of improvements in the later generations. The Gen 1 had many sensors made of ordinary potentiometers that would become noisy after a while, leading to various classic symptoms (search for "big hand syndrome", "steering gear jitters", "mouse in the heater", and so on). Toyota started right away in the next generation replacing most of those with non-contact, inductance or Hall effect sensors to avoid those kinds of symptoms. Gen 1 also was the only generation with a belt-driven A/C compressor. The air cooling only works when the engine runs. If you are sitting in traffic in hot weather, the engine will be frequently cycling on and off to run the compressor. All later generations have an electric compressor, so the engine can stay stopped and the A/C continues to work. Also, all the later generations have the hatchback shape, more versatile for cargo, and comfortable enough to sleep in (popular for camping, given the way the heat and A/C can work without the engine constantly running).
