I've brougth SOYOs, EPOX, QDI, MSIs, BIOSTAR, and had a number of repairs on PCCHIPS, ESC, and CHAINTECH.
My K6-2 with SOYO 5EHM worked good, some selfbooting sometimes, every 3 hours but nothing else. I change it for a Epox 7KXA and Athlon slot A, after changing memorys for quality brand, and deleting a coupple of files form MSBACKUP on Win98SE, that cause reboot and a green line after loading desktop (see "Green Line Issue" on EPOX FAQ), the mobo workwed fine, but of course, the overclocking abilities were poor.
Then I buy my first ASUS mobo, the A7V, very nice board, diferent design, it was obious that this one was not a copycat of the VIA general Prototipe Board, and worked really good. Now I have an A7V133.
I sow working the SOYO Dragon + and the A7V266-E, and the ASUS worth the extra pounds. In the SOYO I was unable to overclock an Athlon 1200, just to put it at 1333Mhz, (10 mulltiplier x 133Mhz bus), after setting those values en BIOS, the Dragon doasen't boot anymore, and I was forced to reset the BIOS with the jumper. This mobo don't boot again in default settings after you reset it form a falilure overclock, as the ASUS A7V133 and the new A7V266-E.
Of course, a wanted to change my A7V133 for the 266-E, and couldn't do it for the price, but I'm saving and some day I will, the diferent in performance betwen the 133 and the 266-E were at least a 35%.
So for my personal experiencie there are only 2 brands in mobos, Intel and ASUS, and since you can't put an Athlon on a Intel board, there's not much of a choice...