I didn't have this one (I had a TK-90X, and a TK-95 after that; both could be described as improved Spectrum clones) but I briefly used one at a place where I took some programming course in the 80s (they had these, and Coleco Adam) and I loved it.

Last week I was at a conference at the Computer History Museum in Mountain View and saw one of this in real life for the first time in, easily, 38 years, and it brought tears to my eyes.

If you're ever near this place, I recommend a visit to this museum. It was my first time, but it won't be the last. I hope I can go back and take my kids there once. I left with a punched card with my login name punched into it, using the keypunch of the (working) 1401 that's on display.

I believe that I got the first external cassette drive for the PET on the west coast. Only used it a very few times. The big boost was when I got the floppy disk drive. I could do anything!