I got a demo of both the Anton Paar certified unit and the equivalent Rudolph unit. They are very similar; it turns out that the guy who started Rudolph used to work for Anton Paar. Contrary to some of the pricing posted above from a couple years ago, the pricing I got was around $15,000 for the base units. Of course you can add various options which will increase the cost quite a bit. Anton Paar offers a bunch of options; Rudolph not so much. Both units come with Ethernet and can print right to your laser printer.
Both units functioned similarly and were very nice to use.
With that said, there are a few drawbacks for these machines in general.
1. They are very, very slow. They take several minutes to stabilize and give a final reading. Depending on how fast your thermometer gets to a stable reading, you might find using hydrometers to be faster.
2. You have to be meticulous about cleaning out the machine between samples with RO water. Then you have to run its air blowing cycle (or whatever they call it) to get all the water out. Any trace of water or the previous sample can throw off your next reading. When you add in the cleaning time, it slows it down even more.
3. Neither company offers any calibration service. At least that's what the sales reps told me. They do offer a maintenance service, but they made it clear that it was not a calibration. Both sales reps suggested measuring distilled water on a regular basis; if the water measurement was correct, the machine was in spec.
In the course of the demonstrations, I tested some of my bottled product and found it was within spec. In some cases, I was within a few hundredths of a degree of proof to the machine results. So you can do just fine with hydrometers. With that said, for any larger scale operation, or even a medium-sized distillery, getting one of these units would be a good idea.