I've tried a few other distros every so often, to see what the alternatives are like. I've never got past the installation on any of them, although I have only tried the top ten or twelve.
The main problems for me are the latest seem to want to do everything and give no options; useless for people who want to be able to do disk partitioning, use LVM and cryptsetup in the installation.
By comparison, I've set up Windows 8 and 8.1 on friends computers and that takes longer than setting up Debian. I lost count of how many times it rebooted.
Debian stable works. You want stability, security, reliability and something that works, get Debian. Install it and enjoy it.
I think that many of the derivatives are probably due to desire to personalise more than improve. Of course, with it's popularity and the number of users,there are going to be many varying thoughts about which way to progress.
And for those who don't feel comfortable with Debian, there are hundreds of other distros; probably enough to suit everyone. If not, then you can join the growing number rolling their own.