I asked the same question a while ago; I settled on a couple of them but never found a favorite.
I think it's something like text editors, where personal preferences come into play and there's not really a "perfect" one for my needs. I haven't had need of one again for a while so I've forgotten why I preferred one over the other.
I think it's a pretty niche tool, which means there won't be a heck of a lot of innovation or competition. Every time I need a hex editor I *really* need it, but it's only for a few files.
I'm not sure if UltraEdit was mentioned in that thread but it had a really competent hex editor. It's $60, but has a free trial that might last long enough to get you through what you need. The only reason I don't have a UE license is I prefer gVim for text editing.
You'd think by now this would be such a well understood requirement with obvious good and bad ways to go about things that every decent IDE would include such a thing as an applet. But nooooo.
The funny thing is that despite having used many over the years the one that seemed most comfortable and efficient was an old MS DOS hex editor I can't find anymore. I think it was part of a toolkit of utilities from the old 1980s WordPerfect company or somebody like that.
I'm not sure if UltraEdit was mentioned in that thread...
Yes, I mentioned it. However, for hex lately I've been using Gizmo Editor, just because it is part of Gizmo Central (a powerful integrated freeware suite). The editor is also available as a separate download.