I dont know if there are good and bad ones as of yet but I just bought a ATC refractometer off Ebay for $31 shipped to me. The ATC stands for Automatic temp compensation so its also great for brewing beer and taking sg readings of hot wort. It came with a case and is made of aluminum.
I agree with Wade. Get a ATC one. I also got mine on EBAY. BTW I think they only measure BRIX and not 2 scales. All you need to do is convert brix to SG.
I have one for when I make BEER. I can add a HOT sample and get a good reading.
Now for WINE, Are you gonna make from grapes? If so the get one if you plan on picking. If making kits I see no advantage. Make sure you have at least TWO hydrometers. That will be your best friend in winemaking.
I bought a refractometer some years ago and immediately whished I had bought it earlier. It is a great tool when dealing with many batches of wine.
- With ATC temperature is automatically corrected when
doing a reading. So no hassle of cooling down the must etc.
- It only needs 1 drop instead of a testing tube full of must
to do the reading.
- Reading is easily done and not obscured in a foaming must
as with a hydrometer.
- Cleaning is a matter of a secons. Just wipe the screen
with a paper towel or something similar.
The only setback is that it is more difficult to
do a 'running test'. Meaning that once the must starts fermenting
you can not do an accurate reading because the alcohol interferes with the reading. You need to use a spreadsheet to convert the readings at that time.
But hey: who measures SG anyhow after fermentation has started ???? I have never done so.............
And before anyone starts wondering: indeed I also never do an end SG reading when my wine has finished. The only exception is when I do tests for my web-log.
I have a web-log story comming up which discusses the refractometer in great detail with pictures.