It comes with two 10gram(I think) check weights. Super easy to calibrate using them also. I do not have a high priced scale to compare to, but I think it would pointless in a way.
When working up a load you're only looking for repeatability. It honestly would not matter to me if the scale was of .5 grain because all I am wanting to do is consistently throw the same charge once I find what my gun likes. It would be different if the scale was off a lot, like 2 or 3 grains, but I am next to positive it is not. I have worked up many loads in many guns from small 9mm cases up to big 375jdj cases, and had velocities match real close to what published data gives. So in the case of like the 9mm, when your only working with 5-6 grains, it must be real close or else I would be having some issues.
The only time I can think that it would matter if a scale was not as accurate as a scientific scale, is if you had two different loading rooms/stations, and you worked up a load on one scale, then wanted to weigh the same load amount on another scale. If they both did not weigh the same then you would have an issue. I only use one scale, so I do not have this issue, but it could easily be worked around by simply weighing the load you want on both scales and writing that down in your book.
Long story short....
.......I have complete confidence in the scale and have used it long enough that I would recommend it as reliable. The only complaint I have with it is that it will shut down rather quickly when not in use. That's only an issue when I am not on a roll making up rounds.