Is there any way to tell which version a vendor is selling? Or is it a crap shoot (except for physical changes to the exterior)?
The model number is unchanged, KA3005P, and I would not trust the vendors to update the pictures on their websites. So I would specifically ask the vendor about the changes which are visible externally -- the "LOCK" instead of "M5" label on the LED is visible with the unit turned off, and the green digits for the voltage are obvious when it is turned on.
Is the fan any quieter?
Under light load the fan is very quiet -- much less audible than my Siglent SDG2042X, which in turn is much quieter than the Rigol DS1000Z scope. When I short the outputs in the 30V/5A setting, the fan gets cranked up gradually and does become louder than the Rigol -- but I can still tell whether the Rigol fan is on or off, it does not get drowned out.
The noise one hears under load is from the airflow, not from the fan bearing, and is not unpleasant in pitch to my ears. The fan speed control is temperature-dependent, not simply derived from the voltage/current draw. It is not "nervous" but ramps up and down gradually. Hence I would say Korad did a decent job within the constraints of the fan size.
This one [memory button behavior] is very annoying. And at odds with common sense and proper behavior. Essentially, you have to give up one of the presets so that it can become the "current setting". "Current" meaning time, not electricity.
If I manually tune the radio in my car it doesn't change the presets. Nor should it! Changing the power supply preset should be just like the car radio...long press to save.
Yes, that one is a disappointment. Seems that it would have been very easy to improve via a software change -- e.g. by requiring a long press of a memory button to save the current setting to it. Maybe next year... ;-)