My first computer was a CBM 3032.
This was basically a souped up PET:
-32kByte of memory instead of the standard 4/8kByte.
-Bigger and more crisp Screen - but green instead of white.
-an additional ROM socket for easy expanding
-and the most importand part: a much, much improved keyboard.
The really good keyboard of the CBM3000 series was the main reason why Commodore managed to catch a big chunk of the business office market.
I started with a tape drive, soon to be supplemented by a unlicenced copy of the CBM4040 double disk drive and a CBM 3022 printer - you wont believe how large and loud this printer was.
There was a lot of software available for the CBM Business machines, I would even dare to say between 1978 and 1983 it had the best library of all systems.
When I switched to the C64 years later my main reason was the high compability of the C64 towards the older PET/CBM-systems: You could switch the C64 into a CBM compability mode which allowed to use lots of software and even load some ROM programs into C64 RAM and use em. Guess most people didnt even know this feature about the C64.