Well, I´m not dependant on the saw, but when I need it, I need it as quick and eficiently going as possible. And being a firewood hack time from time, it is somehow close to me.
For as they are described here, from the low end of prices, my vote is definitely a 620-120, hydraulic asist is a no-brainer. For each type of chain one, permanently set up. Oregon 510/511 permanently set up for doing rakers. Using their HF unit for rakers might be tempting, but with the flex in these parodies it will be just a wasting of chains and source of frustration.
Sure as hell they should learn how to touch up the chain in the field, but better to hop a new loop on the bar and go on in some cases. Firewood operation is not about sharpening, but about repairing marred chains good part of time. Yep, the best wheels availible and dressing tools too.
I understand some people here having eyebrows rised that they don´t file on their own. But guys, you cut mostly clean wood-and I mean even those oddballs the yarder operator used to dig trenches under the line. Cutting flashflooded hardwoods (like beech, oak and black locust) from a WWII battlezone/former army training area, full of dirt, sand and shrapnels gives you a lesson in 20 minutes. The same with some wood from former pasture lands-wires, chains and nails there.
In this type of operation, nothing beats a fresh loop of chain, or having possibility for 10 minutes break to run the chain through a grinder you don´t have to set up for anthing else than cutter lenght. No way to set back the cutters 3/32" with a file in such a time. Or-you can if you are a filling master, but the bill for the files will crush you.
my 0,02
