I've been using Firefox since a few days before the 1.5 release. I was using RC3, so it was basically the final 1.5 release, anyway. To me, it has really improved in 1.5. There were a few things about 1.0 that annoyed me that they fixed in 1.5. The thing I like most about Firefox is that it doesn't seem to use nearly as much memory as Safari.
I figure Firefox will be my browser of choice for a long time.
I figure Firefox will be my browser of choice for a long time.