"Best" Eddystone model ?
Well, I think it all depends just what your primary aim is and what
crierion your going to use. You also need to make allowance for the
vintage / available technology when deciding on any particular ONE set.
From my viewpoint - for operation within Amateur radio freqs. only -
I've always rated the 888A as a receiver that takes a lot of beating
for overall performance, ease of use, flexibility under various signal
conditions, pedigree of design, maintainability, size / weight, amongst
other desirable attributes.
On the other hand, considering the shortages of everything just after
the end of WW2, the S640 is quite an achievement.
As for the EA12, the only thing that spoils this for me is the tuning
scale - which is back to front! Otherwise a v.g. rx.
Of course, if it's sheer technology that gets your vote - then there's
always the 1650.
Al / G8DLH