To be honest Ubuntu is one of the easier linux programs to use. Where did you get that quote from, because if it is from a site pushing PCLinux that is obviously why and it is biased. I am using ubuntu 10.10 right now and i don't have any complaints. The only reason some people may say this is because ubuntu is running the gnome desktop enviorment, which is a lot different from the windows setup. Does that make it worse, no. That just makes it different, and i suppose people who don't want to take the time to actually look to see how easy it really is brand gnome as hard. Granted you can get almost any desktop enviorment for any distro now, so i'm sure they have gnome for pclinux too, and ubuntu has kubuntu which is just ubuntu with kde instead of gnome.
In terms of actually usability ubuntu is actually one of the distros most often recommended to start using linux with. Their are a lot of debian files out there, and i just like DEB better than the RPM packaging tool PClinux uses. But again that is just preference.
For basic tasks ubuntu is really easy. You hit download from the software center and download whatever you need, and it is already on the toolbar for use. There is a wifi icon to click on to set up wifi, and to start the Internet you just click the Firefox logo. however, there are also limitless possibles with the command line and custom additions to the distro that make it as advanced and fun as you want it to be.
Ubuntu is pretty easy to use. it is the first distro i used after switching from PC and i caught on pretty fast. I still use it now and i love it. Generally, it is just opinion though. No distro is really better than the other for all around use. If you were going for a focus on a particular feature (like computer graphics or something) then there are certain distros that are superior to others. For everyday use the best distro is just what is easiest and most comfortable to you.
I would recommend getting UNETBOOTIN and installing it on your flashdrive to try to bootable versions of these distros. That way you can mess with it for an hour or so, and if you don't like it just try another one until you find one you like.
Anyone who says that one distro is better than another without backing it up is just saying an opinion. Unless you plan to focus on a particular feature there is really no "best distro." Just the ones that are easiest for you (and of course the ones with the coolest programs.)