I've loved tmux for since before I can remember (which can mean more than one thing at my age...).
I changed the prefix to Ctrl-a not too long into my tmux journey, though.
I think I did that primarily for speed, but wouldn't be surprised if there were a shortcut conflict involved. If so, I can't remember what it was - possibly for having avoided it all these years?
I think Ctrl-a is for "screen", which was my first multiplexer. I'm also tempted to change it, but there are so many different systems that I ssh into in which tmux is installed and my bindings not, so I've made peace with using Ctrl-b :-)