Tascam, then Teac, was one of the major driving forces behind home recording, some would argue the driving force.
Back in the early to mid 1980s I did maintenance work in a number of Teac/Tascam based studios. The really early gear was reliable, and maintainable, and a little annoying since working with their single-ended audio interface was at best challenging.
As the market grew they started to cut corners. The Model 38, and Model 58 certainly had more/better features, and I suppose looked cooler, than the 80-8, but I have an 80-8 that still works, and a lot of the 38s don't (undersized motors were a problem, and the custom chip that controlled transport functions is nearly impossible to find). The 58s fared a little better because their motors were up to full time use. I wouldn't turn down a 38 today because it would not get heavy use, but it was a problem back then.
Their boards followed the same arc. The Model 15 was amazing. Dead quiet, flexible routing (for the day) and very easy to work on. The Model 700 was an excellent console, but by then I think they had damaged their reputation, and they did not sell as well as they might have. I worked on quite a few 500 and 600 series mixers, and they were not a lot of fun to keep working.
Teacs real gift to the recording community, however, was their early manuals. If you can find copies of the manuals for the M15 or 80-8 read them. There is a wealth of good information in there.