I'm one of those Linux users that is hard to satisfy. I like several featuers, but it only takes a couple problems, no matter how catty or picky, to make me switch. And I have switched Linux distros a lot.
My first exposure, was actually an AIX system that my uncle administrated for a local business. I would sit in his office, playing games on one computer while he worked on the other. Most of the times, I mimicked his command line typing pretending to be running my own business. Well, needless to say, he created my own account, and began teaching me how to use the system. I was hooked.
My first personal installation, or actual attempt, of Linux was Slackware. I didn't know I was attempting the most difficult distro at my first go around. After hour after hour of trying to get it installed, I gave up. It just wasn't working, and left a taste in my mouth that all Linux must be like Slack.
A few years later, after I bought a laptop, I tried again, this time with RedHat. I successfully got it installed, but X wouldn't come up, because of the laptops manufacture-modified hardware. I learned how to modify the XFree86 settings, and eventually got it up. There were a number of other problems, however. ACPI, wireless, stand-by, hibernate, touchpad and a number of other hardware issues weren't working, and giving me a big headache.
After not long, I tried Mandrake. Mandrake configured my display and ACPI properly, but there were other problems that required a ton of tweaking to get working properly, such as the touchpad. Also, with the kernel as hacked as it was with Mandrake, downloading the sources and recompiling introduced all sorts of new problems.
A firend of mine told me about SuSE, and how he liked it, so I switched to that. I stayed with SuSE the longest up to this point, as everything worked almost flawlessly except wireless and standby. The only problem, was SuSE felt exceptionally bloated, regardless if I used Gnome or KDE. But it kept me happy. The biggest issue for me was dependancies.
After a hard drive crash, which caused me to lose everything, I thought it would be a good time to try a new distro. I visited distrowatch.com, and Ubuntu was #1 on the list. I read the reviews, checked out the screenshots, and read forum posts, including many here. I gave it a shot, and I am not turning back. Synaptic completely converted me to Ubuntu.
While wireless and standby are still not working for me (I don't think there is a distro out there that will help me much with it), I love the distro. I have it running on 2 computers, and use the live CD when using my wifes iBook. This is the best distro that I have used. It is a solid distro, and I love the community here in the forums.