What made them mad geniuses? I saw their equipment from time to time in catalogs but was too young to realize they had some kind of special reputation.
https://en.wikipedia.org/wiki/ABIT_BP6 is a great example. It was the first motherboard to allow the use of two unmodified Intel Celeron processors in dual Symmetric multiprocessing (SMP) configuration. Not only did this cost drastically less than purchasing two CPUs certified for SMP from Intel at the time, Celerons of the era were the first Intel chips with on-chip L2 cache which was clocked at the full speed of the CPU as opposed to the off-chip L2 cache's half-CPU clock on the Pentium II. Abit was also one of the first companies to include jumperless overclocking features in the BIOS.
If you look close, you can even see the blue thermal sensors Abit placed in the center of the CPU sockets (CPUs had no built-in thermal sensor at the time) which greatly eased overclocking.
In short, they made boards that gave you the full range of what was possible, not just what was on the marketing sheet for the CPU.