I read about the available computers and needed both the speed and cadence, since I wanted to train for a long distance race. Based on the reviews and opinions, I settled on the CatEye V2.
While I was waiting for the computer to be delivered, I downloaded and read the manuals. One common strain in all the user reviews was the not-so-easy install. I was prepared for this and got some extra nylon ties and mounting tape ready.
Once the computer was in, it was as I expected. The speed sensor and magnet was easy, but getting the cadence magnet set was not easy. The recommended distance between the sensor and the magnet was 5 mm, and there was no way I could get the distance to 5mm. FYI, I have a Trek 7.3FX. Some serious mounting tape later, voila, I have both speed and cadence. Computer set-up took 5 minutes. Rim size and units set up, I took the bike out for a nice long ride.
On a 40 mile trek, I have observed the distance measurement to be pretty accurate. I used the mile markers along the bike trail and found the distance to be off by 0.5 miles over the entire 40 miles. The cadence and speed measurements were accurate too (calculated the average speed using my stop clock and the distance from the mile markers). The wireless transmission was never off, even when I was passing power lines or going over some serious bumps
The buttons are a little hard to press and I had to use my finger nails. The backlight was effective even in daylight (haven't tested it out in the night yet). All in all, a very nice computer. Wish CatEye would have provided an option to download the files to a personal computer.
PS: On the way back, the cadence magnet was knocked off kilter. I guess I have to anchor the magnet more firmly to the crank.