I dunno, some of those old portastudios were rock solid (many still used by student-age indie bands near you). The 424 mkII is a classic with a strong cult following. Certainly their cassette multitracks were not any worse than Yamaha's (I used both as a youngin)... I don't recall any other brands even being available here.
It's all moot however, because the era of the hardware portastudio (and any audio medium requiring any moving parts) is pretty much over anyway (some exceptions, large format tape in fewer and fewer pro studios, niche hipster use etc; negligible), which is why Tascam makes DAW interfaces now. Personally, I think the strength of the company is in their more specialized products (audio interfaces and recorders for DSLR cameras for example - not nearly as crowded a market as prosumer level interfaces, though also not as lasarge, but large enough, and they'd never in a million years convince pro audio engineers that they're at their level now.... film guys on the other hand, already use their stuff all over the place, but even there, I'd have to concede that the Cadillac is not in Tascam's product line).
Gibson has been going more high tech recently, what with that robotic Les Paul that I barely glanced at, so it does make some sense to acquire Tascam, who has the design and production capacity to handle what Gibson needs.