I am puzzled from time to time however by little things. For example, I was updating some information on a site and entered a date in the required mm/dd/yyyy format.
The edits rejected the date.
I emailed the site about "their" problem.
I tried again a couple of days latter. Surely something as basic and as common as that edit would be fixed. It wasn't.
So I clicked up my old Netscape 4.7 and tried the updates. They worked.
There are other examples such as a recent "drag and drop" requirement in a site's window that Firefox refused to do.
I have no plans to try it with Netscape 4.7 and no plans to stop using Firefox. One day I'll learn what to do about the above. No hurry.
I primarily use Firefox. However, it does have quirks such as the way it deals with cookies. I like my Cookie Pal in IE much better. I've never had one popup using Firefox. And most of the time it's faster than IE. Plus IE has added two more rows of useless icons which clutter the screen, whereas Firefox doesn't add anything.