I had a Technosound Turbo 2 back in the day and was quite impressed with the software.
Yes it was one of the only ones to allow direct recording to hard disk. For some reason it used it's own proprietary format for that and not iff. I did write a convertor back in the day, if it's not on aminet then I'll see if I still have a copy of it.
The only thing I remember using it for was sampling
http://en.wikipedia.org/wiki/Backwards_(Red_Dwarf_episode). My VCR could play video backwards perfectly at 1x but it was silent. There were very few people outside the TV industry that would have been able to watch it in the order it was filmed in the early 90's (it was broadcast in 1989 but there were no hard disk samplers for the A500 back then).
I had to write the software for reversing the sample as well. I'll see if I still have that too.