I agree the 'official' method is a PITA, especially if you buy a computer that comes without any recovery media, but its still possible.
Gareth seems to be paranoid that after a year the Windows update will be pulled from the update servers and put behind a pay wall, which it won't.
Just like the W8 pre order update, all that will happen is the price will change. Nobody who bought W8 updates cheap on pre order was then asked to pay again once it went up to full price.
It's all a moot point anyway as I'm 100% certain there will be an ISO from MS. And if there isn't then there will be ISOs available through other means.
If you take the free update you will not be charged for W10 after a year. I guarantee it.