What he said
TReilly is right of course. "Mail order" sails CAN be adequate in build quality-it is a hit or miss proposition. But when it comes to shape and true proper fit for the boat, these sails generally don't cut it
(in comparison to the "real thing").
Small measurement details like tack cut up or set back, outhaul ring set up, location of the first mast slide/slug from the tack-use of a jackline or not-these can be guestimated and you usually end up with a sail that is functional
(USUALLY), but you may have annoying wrinkles out of the corners or similar complaints-you will get what you pay for.
But as a side note, while not one of the big boys, Dave Hodges (aka "Hodgepodge") is a top quality sailmaker, and Rolly Tasker, while a mass producer, has a good rep for quality-but unless they really have dimensions for YOUR boat-not just generic or average numbers-the fit will be hit or miss.
I know this is sounding like a broken record, but I'm trying here to give some specific reasons why these "bargains" may not be so hot.. For another 10-20%, I will take a proper fitting sail and the increased resale value of a name brand sail for my high quality sailboat..Now, if we were a bunch of McGregor sailors......
S