I have a GL1 and I had problems with the heads after less than a year (artifacts, “holding” part of the frame). I sent it to the Canon service and they charged me for cleaning the heads. They said that the found parts of video band in it. OK, fine. This was 2003. Since then I have been 3 times, always with the same problem. The last one last november. I filmed now about 10 hours and back to the same problem.
I met this guy who has a GL1 and a Sony 150, he told me he has the same problem with the Canon, but never with the SONY (although he uses the SONY as camera and video deck).
I use some good quality JVC bands, it shouldn’t be a problem with that.
Anyway, even if I like the colors of the Canon gives I decided that my next camera will be a Sony.