Normally the tone on this forum is pretty civil. What happened?
I'm not an accomplished filer by any means, but even I know enough to say that filing takes some time and attention to learn. I cheat: I use a grandberg jig about every other or at least every third filing, and every time I rock out a chain. In between I just follow the angles from before.
I get good results; I know I can do as well as any of the local grinder-hack shops do, and can make at least one look like an idiot. I think learning to get the best out of a grinder, any kind, probably takes a little effort too, so maybe oakman has spent his effort learning to use the litle grinder effectively. His choice, I think.
As far a changing a chain out in the field, it aint that bad, and you don't need air. I keep a few tools in the truck, including an old windshield snow brush with a broken handle, a can of wd-40 and a rag. I brush the crud away from the gas and oil caps, and wipe clean. Same with cleaning under the clutch cover...just use the wd-40 to dislodge any particles you can't get with the brush. It really only takes a minute.