I have had some nice QSO’s on 20 meters. I had to turn the power down to 2.5 watts because the power supply I was using got quite hot. The FT-817 does indeed use a lot of Amps when running at 5 watts and 14 Volts.
Best QSO so far was EA/HB9BMD using 2.5 watts. He was running 10 watts into a dipole and his signals were up to 589 with quite a lot of QSB though. The band was closing. Besides the small annoyances that I have mentioned before, the receiver is very good for everyday CW use. I have not tried it in a contest nor a pile-up but I wouldn’t even expect this damn small thing to do any good under those conditions.