For quality, performance and range of products, I like Panasonic which back in the classic years, was one of the largest if not THE largest brand out there.
JVC produced good products but had a very small lineup. Sanyo's of the '70's and early '80's were great but again, limited lineup.
Marantz offered only top quality stuff but had a teeny lineup relatively speaking and not as well known so they didn't sell as many as Panasonic or JVC or Sanyo who cranked them out like cookies. Since Marantz specialized in the audiophile marketplace back then, the portable gear market was not their bread and butter. But they did offer some very pricey professional gear for journalists that was bulletproof. I still think of some of their models as being the best kept secret around. Perhaps because I owned the huge $$ Marantz home products back in the day, I have an affinity for Marantz gear.
Sharp -- good products, good quality but most of their stuff have........... "sharp" sound.
Aiwa offered some terrific stuff and I don't know any of their lineup to be junk or beginner cheapo models but they couldn't compete with the Panasonics of the world.
Toshiba was....... well, just another brand back in the day. Not usually the first brand that jumps from the tongue when asked to name a brand.
HItachi...... same impact as Toshiba. An alternative to the large major players. Not better. Not much worse, just an alternative.
Sony.... Good quality gear. Styling couldn't really compete with the more flashy classic looks of the other brands. Also, didn't have the "guts" of some of the other brands/models. Expensive pricing which probably resulted in lower volume of sales.
I probably forgot a brand or two but these are for the most part, the majority of the major boombox players.
THE REST were all small lower quality players. If they didn't offer service manuals, they fall into this group.