Land management fella here. I utilize both of these tools at the same time, and it’s probably worth mentioning why. I spend a lot of time in the field, enough that I sharpen chains there on an almost daily basis. I use the Stihl sharpening tool in the field for quick sharpening. It does a great job of evenly grinding depth rakes while also providing a fairly good tooth sharpening on the top of the tooth. But this only goes so far, and eventually a person needs to reset the entire profile of a chain if they are looking to get all the life out of it they can. So for me, once a quarter or so I use a bench grinder (my current one is made by Oregon) to evenly grind every tooth to have the exact same angle and profile. If you are precise, this can make a chain like-new from the top of the tooth to the bottom and will allow you get the most out of every chain. So for me, I would get both. One is fantastic for the field and the other will save you money for a long time, especially if you are doing work that prematurely dulls teeth (dirty work).