I've had Cateye equipment on various bikes for about twenty years and all of it has lasted well. The first items were pair of bike lights, front and rear of a clever design. They're a bit worn from years of night commuting but they still work I haven't had their cyclometers quite that long but they're also pretty tough.
I have two, a MITY2 (CC-MT200) and the CC-HB100 with heart rate monitor. The MITY2 has gone down the food chain to another bicycle, replaced by the HeartRate version.
The HB-100 has some problems with the heart rate suddenly going to zero for a consistent four or five seconds every so often. Cateye, on their web site says that is is due to radio interference, but I'm skeptical since it happens at random points on the ride, not just in particular areas where you might expect underground power lines. It happens in the countryside and it usually comes back quickly. Sometimes, though, the heart rate sensor truly gets out of position, but then it's out until adjusted.
A further problem seems to be the contacts between the computer and mounting bracket. They seem quite sloppy and sometimes I've had to move the cyclometer around on the mount to refresh the contact. Finally I resorted to placing blobs of solder on the computer contacts and filing them down to size. Now it make very good contact.
The big beef I have with Cateye is that the sensor attachment for the front fork only fits department store small forks, not carbon-fiber wide forks. I emailed Cateye with this problem and the response was that they were working on it. Although the larger carbon-fiber forks have been around for many years they hadn't quite gotten around to accommodating them. Somehow I can't see a hundred dollar cyclometer used on a hundred dollar department store bike. At this time they offer the Extra Large Fork Bracket Sensor Kit- (Applicable Fork Diameter : 11~50mm), part number #169-9770 for about $13 USD.
I've built my own sensor holder, which is a worthy substitute. I removed the sensor body from the jacket that attaches it to one half of the fork connector. You're left with just the jacket for the reed switch, and the reed switch with it's wire. I built a simple electronic circuit using a 14 pin 20 nanosecond cache memory chip scavenged from a 468. Any 12 to14 pin chip will do, but the faster the better. When I say it's a simple circuit, it is, having only one component. The chip is placed on it's back, a piece of that nice self sticky tape (not two sided - this stuff just sticks to itself) is curved inside the pins and the sensor placed in the little nest. Before attaching the sensor you can wrap a bit of the tape around the joint between the reed switch assembly and the jacket. This assembly, which should stick together with the sensor is cable-tied to the fork.