I actually used ones from Argos in my house for duvets etc and they worked brilliantly. The only issue I have is that for longer periods of packing, for example, if you were going to sent clothes/bed clothes by crate, then you maY get mould. An article I read mentioned not to wrap clothes in plastic as the condensation may spoil the items as they go through the tropics. Also you may find some clothes get irreversibly creased on a long journey.
An excellent idea however for the plane journey. I will file it for my trip there in a few weeks!