I just chunked mine two nights ago. It quit working. The light would be on, but the tank was still colder than it should've been. I used it for a few years though.
I got one almost 10 years ago and still works fine for me. Had a small incident where I did a water change and forgot to unplug it. It started to smoke, but unplugged it and tested it a few days later and it was working fine.
I bought some because they were on clearence from Foster and Smith. I ended up returning them. The 150 watt couldn't even get a 20 gallon to 80 degrees.