I personally prefer Red Hat 6.2. I tried SuSE 6.2, Slackware 7.0, and Mandrake 7.1, and found them to be full of bugs. For example, when Mandrake 7.1 asked for the extension CD (CD 2), it failed to unmount the CDROM drive, which means I couldn't use the second disk. Frustrated, I used a paperclip (I wanted to use the second CD) to open the drive and place the extension disk in the tray, and when the drive started reading the disk the computer froze. I wonder if Mandrake does any bug testing at all. I also could not get my network configured (I have a D-Link 530 TX+ using the VIA Rhine module).
In SuSE 6.2, installation was fairly easy, but when I connected to the internet using KPPP, I could only access the Internet by typing the IP address instead of the Domain Name of the server like usual. Using Yast, I tried to specify a Name Server so that I could use Domain Names, but every server that I specified wouldn't work. I also couldn't disconnect from my ISP by pressing the usual combinations of buttons (I think it was Ctrl C), I had to unplug the cord from the wall.
Slackware was the worst of all. It was fairly easy to install, but configuration was a pain. I tried to configure X using the xf86configure utility (text), and chose the 'Microsoft serial 2-button mouse' option and the correct port. When I started X, the mouse would not work properly (it acted like the buttons were being pressed down constantly).
I am fairly new to Linux; I usually try, get frustrated by the bugs and lack of user friendly-ness, and then put beloved Win 2000 back on. I just bought an old P200 MMX that I am going to use as a gateway to the internet for my other two computers (and to finally play around with Linux without suffering from the lack of software and hardware support). I have installed all of the above distros on the computer and all have failed miserably due to the exact same bugs I have always had problems with. Only Red Hat 6.2 has not given me the same problems. It is the cleanest, easiest install/configuration that I have ever done (easier than Mandrake 7.1).