I live nowhere near the PNW...I'm sure I'll want to keep round filed chains on hand. There is no "cheap" way to get into square ground equipment, but why buy two grinders? Right now I'll keep round semi-chisel on hand for stumps/trash. Instead of my line up of round chisel and round semi-chisel I'd like to move to a square-chisel and round chisel line up.
If you're dropping that much coin on a grinder why buy one that can't do both square and round?
I've held off on buying a Silvey 510 partly because of price and partly because I've never hand a ground chain turn out as sharp as a filed chain.
I've never ground my own chains but this experience seems supported by guys on the web that DO grind their chains.