And the Celeron 300A was definitely a contender for best cheap CPU during that pre-Athlon era, especially given how overclockable it was. Later there were also a couple of inexpensive socket 370 motherboards which could accomodate two processors, so a few people had pretty kickass early dual-CPU setups for a good price.
I remember the lack of an L3 cache was a real pain. The ones you remember were the later models. The first model was a Slot-1 "cartridge". I still remember the legendary Abit BP-6 motherboard.
Yeah it's true those weren't the very first model. Seems the 300A was ~four months after the initial Celeron (April '98 Celeron launched, August '98 300A released).
They were not the best CPUs at all