Yay another Mandrake user! I actually bought the box from a computer store back in 2003. Mandrake was actually a decent effort for a user friendly distribution and the standard installation included tons of software. Getting pppd to connect that serial ISDN modem to the internet for the first time was magical. I’ve been a Linux user ever since. The other main alternatives at the time were Debian, Slackware both too complicated for a newbie.
Ubuntu was a fantastic distribution to start early on. Especially in the pre-10.x days there weren’t many beginner friendly ones. Your alternatives were Debian with very outdated software, SuSE which was kind of OK, Fedora which was also quite unstable and lacking packages (remember hunting RPMs on the old RPMfusion?) or Ubuntu. At some point I’d outgrown Ubuntu and moved on to greener pastures. Nowadays I’m not sure I’d be recommending Ubuntu to new users, Fedora is quite good and without all the snap store shenanigans. Even Debian installation experience is not too bad and it’s not lacking too much in software.