Hi, Martin! By "interesting" do you mean "fun"? A former supervisor of mine once ordered me not to use the word "fun" at the corporate office in Indianapolis, because upper management would take it the wrong way.
I agree with you on all points. I haven't measured the noise floor of either receiver, but on 20 meters it doesn't really matter. Maybe it does on 10. A good soundcard makes a big difference. What we call an "SDR" is really just a front end, the receiver is comprised of the front-end, soundcard, and DSP software. The FT-817 probably is a bit cleaner overall, but it isn't nearly as versatile. The SDR is more "fun". Oops, I mean "interesting". 73, Pete, NI9N