What does being tube or transistor really have to do with how good the
reception of a receiver will be anyway? Nothing, as far as I know.

Nothing really...There are good and bad of both types...
The real deal in hearing something like that is selectivity.
And unfortunately, that usually means more $$$$ for the radio..

If you have the selectivity, you have it half won...
The rest is using the antenna/s, to null unwanted stations.
Now , some tube sets might *sound* better to the ear, than
some solid states, but thats a whole nother thing...
It's the filtering that is the main thing as far as the
audio quality. My icom has real good audio on AM, if you
are using the wide filter.
A R-390 would probably be real good, as I *think* it has
narrow filters for any frequency, including MW.
So yes, it would be great if so...My old Drake R4 would be
good *if* I had the optional low band converter..The drake
has narrow filters available, and they work anywhere.
But having tubes has little to do with anything, except
many the tone of the audio output. Being the Drake needs
the converter to work MW, the icom 706g is my best MW radio
right now. Hands down when it comes to weeding tough ones
out of the muck. It's "narrow" filter for AM is really
narrow..It makes "next door" local stations go on vacation.
I'm sure a lot of bigger modern rigs would be even better.
IE: the various 756/746 pro's, etc, etc...
MK