Heavyfuel, if she is half as good at stacking wood as she appears to be at sharpening, send her over when she's done there!! Between her and my son, I might be able to sit back and just sip tea while they work!!
But as to the OP, and sharpening in general.... just do it yourself, as many have said here. Learn how to file properly, how to hold the proper angle (~25-30° depending on manufacturer specs), as well as the proper 10° handle-down angle (not parallel to the floor). If you take your time, you can do it. And as far as messing up a chain... so what? If you happen to screw up a chain or two while getting proficient, that is only about $30 down the drain, but not really, cuz you are using them while you are making mistakes. Still cutting wood.
I looked at and considered the Granberg, looks like an accurate tool. But IMHO, too much setup involved. Might be good in the shop, but not for me in the field. I just bought a new 346XP, and got the Husq Sharp Force (Pferd tool)
653000035 Husqvarna Sharp Force Chain Saw File 3/16" | eBay. Got mine with from the local dealer for $27. It is pretty fool proof, takes the rakers down with each sharpening, can be done QUICKLY on the bar... and while I have only used it on the bench thus far, I can see it being a quick and easy way to touch up the teeth when refilling the liquids.
Not everyone can be an expert at sharpening knives (or saw chains), but if you know how to use a saw, being able to sharpen your own chain is a great task to become proficient at. When I bought my saw, the dealer showed me the Pferd, and how to use it properly. He told me he would gladly sharpen my chains for me, but if I learn to do it myself, it's less work for him. And saves me $10 every time. Now THAT is a dealer I will send my friends to!! (He also talked me out of skip chain and gave me an extra 20LPX and a free annual tune-up for buying from him.)