I had an 1970s vintage Atago (not the digital one)
for years, and while it was an expensive thing,
it worked fine, and I felt confident because all
the honey judges used the same refractometer.
Sadly it took a one-way trip down the stairs,
so I needed another. I was very leery of the
RHB-90ATC sold by Dadant, as it was "made in
China", something that most often has meant
merchandise fit only for the landfill.
But Mark (who runs the Lynchburg VA Dadant branch)
offered to take it back and refund my money if
I was not happy with it. He also was blunt about
the cheapest model carried by Dadant. His
comment was "no one should buy it".
The unit works just fine. Temperature compensated,
which used to be a very expensive option, decent
optics, easy to use in less-than blinding light,
etc. It is not as heavy as the Atago was, and
"heavy" meant "solid" to me, but one simply
must admit that any refractometer is a fragile
tool, one that cannot survive being dropped
down the stairs.
If the Ebay model is marked "RHB-90ATC" on the
box, then it is the same exact model as the
one sold by Dadant.
I can't think of any reason why "digital" would
be better or easier to use than the optical
models, as the situation does not require numbers
with 3 decimals. For 5 times the price, it
should have some serious advantages, and I don't
see any.