There's plenty of apps, or even an Excel sheet, that will take care of the offset due to alcohol being present. There are even sites that will help you out. I've used all of the options to date. I like the site the most (google it) but the spreadsheet also works if you have Excel installed.
I ordered a brand new MA871 off Amazon in early June. I've been using it more to check the OG, but have also used it to check the FG. You do need to make sure there's no CO2 present in the sample. Which is easy to do IMO. You just degass the sample and then check the gravity.
I like the MA871 since my eyes are not as good as they once was. I have to take off my glasses to use the manual refractometers. Luckily I can see decently at that distance, but it's a pretty close thing these days. No issue with the digital.
I will say that you need to be sure the bowl is filled with the sample before you hit the 'read' button. Otherwise you won't get an accurate reading. I have been checking it for zero before each session, to make sure it's still calibrated. Easy to do with the included bottle of distilled water. I also have plenty of that on hand for both the glycol chiller and for the PH meter rinsing.
BTW, the current model has a different shell color than the pictures posted by bracconiere. The ones on Amazon are correct. At least for what I received.
https://www.amazon.com/gp/product/B007Z4IN58