The SRIII is my nicest sounding portable but it does have a problem with touchy tuning at the high end of the AM band.
Don't know whether it is a very slight mechanical backlash that is unnoticeable at the low end of the scale but more pronounced at the more
compressed high end of the scale or if it is a varactor tuning issue.
Otherwise a hot performer on AM DX and probably deserves more than 3 stars.
My SRIII is also touchy between around 1300 and 1600 or so. I think it's the way the varactor tunes, plus the mechanical backlash of the dial string set-up. I zero in carefully when tuning that range...
Some SRIIIs were quite good, and if you got a good SRIII you got a great performer.
Only drawback on mine is a bit of overload in two spots on the dial, seems to mostly dissipate at night, except near 1360, but I live with it...