Since I have an Insight and people ask about it, I thought I'd post some general information about our experience so far. I got this car in 2000, recieving state and federal tax breaks, and it currently has 175,000 miles on it. The vehicle is a 2-seater that weighs 1,887 lbs. We have maintained larger cars for family requirements, so this has been used as a commuter in the Balt/DC, western PA, and WA state areas.
Miliage varies depending on terrain and maintenance. The lowest has been 49 mpg, the highest average 62 mpg. I was getting 49 mpg in western PA where the terrain is very hilly, there's a lot of snow, and where I needed to repair an O2 sensor and some other items that were bringing miliage down. The overall average has been between 59 and 62 mpg. I have a heavy foot as well, but if a driver follows speed limits, for example, then miliage goes up just like with any vehicle.
The car drives and maintains like any gas car. It has a 3 cylinder gas engine and an electric engine that pulls energy from a battery. The battery is powered by friction/heat energy captured from the front axle when the car slows down in gear, so the electric is all free power that is otherwise wasted as friction/heat. Maintenance can go every 7,000 miles, but I take it in every 3,500 or so. Oil change costs the same as other cars, and it uses synthetic oil.
As far as speed, I can merge into traffic with ease since the Insight accelerates very rapidly, and I can cruise smoothly at high rates of speed. I’ve driven tens of thousands of miles on the Baltimore and DC beltways, up and down I-95 on the east coast, and on I-5 in WA, and have excellent performance at speeds up to and exceeding 85 mph. Many small cars shimmy and sway over a certain speed and I’ve not found that with the Insight.
After 175,000 miles, I’ve had one major repair on the Insight, the replacement of the large battery above the rear wheels. To Honda’s credit and my pleasant surprise, the manufacturer replaced this battery free of charge. The replacement came when the vehicle was at 130,000 miles. Many critics site battery replacement as a major hurtle to buying a hybrid, however at 130,000 miles this car had already outlived my three previous vehicles. Therefore, even if I had chosen not to repair the battery, the Insight would still have beaten the best of my previous three cars by over 25,000 miles. On all three previous cars, engines eventually died and were either replaced or the car was scrapped. So, a person has the option of simply trading the car in or scrapping it when the battery fails, or repairing it like they would a transmission, engine, or other major problem that so many cars have as they approach/exceed 100,000 miles.
Complaints are mostly directed at the interior. The seats are nothing like, say a VW Passat's, and they can hurt your back on long rides or day after day. Also, the interior is a bit on the cheap side. But that's about it. Overall, I'm glad I bought and will drive it as long as I can or until I can afford something that performs better.