Based on vectorial synth success by Korg Wavestation, Yamaha were encouraged to build a synthesizer on that side (starting from Prophet VS too), working with waveforms (AWM ) and their famous FM sounds (only with 2 OPs).
TG-33 emerged as a rack version of the SY-22 and as a cheap vector synth option in front of the pro Wavestation. With a 32 voices polyphony (double as SY-22) and 8 parts, TG-33 weak point was their 12 bits AWM samples and the leak of filters, making it pretty noisy and lo-fi sounding that limits it for electronic or industrial oriented artists. It does not have even arpegiator o r sequencer but it can record vector movements in real time as phrases (some like OB-12 and JP 8000/8080 does). Edition is also pretty limited while you can access to hidden parameters from software editors.
It looks very retro and, as you can see on pics, it is more a desktop oriented synth than a rack one. Anyway it can rack mounted with ears, but not in the traditional way but, as it pics the manual, in horizontal position to allow watching the screen.
I personally don't dislike those dirty AWM sounds that, along with FM posibilities, gives me a practical way to build dark sounds, pads or bells. As interesting links I've found the complete (english) manual from Yamaha website: manual part 1 manual part 2 >and some audio demos here and here , and also a software editor and some more stuff.