Some history here. Vector was one of the very first distros I installed; the first was a remarkable distro called Basic Linux, which was based on Slackware 3.5 and could be installed from a pair of floppy disks (and in my case had to be, because I didn't have an optical drive in my computer back then). Then later the same year (2003) I came across an article in Custom PC by a guy called Liam Proven, which in addition to assessing the state of play in the Linux world at the time gave a very favourable review of Vector 4.3. I resolved that one day I would try Vector when I got the chance, and it took me another couple of years before I got a computer with an optical drive and could do so.
I've always appreciated its ease of use and its attractive interface, and also the fact that even when the boot loader breaks you can still boot into it from its installation CD or DVD.
It's also hard to appreciate now in retrospect that back when Vector started you had to edit xorgconfig manually, and if you got it wrong - no XOrg. VASM changed all that. For the first time in a distro (apart from perhaps in Libranet) there was a central and easy to use utility which enabled you to carry out all the system admin you needed to do, and meant that you didn't need to be an IT expert to install and use Linux.
I agree with the others who have commented here, and thanks to everyone who contributed.