what are they actually like?? having never used the 360 store to download anything and my only contact with downloading a film has been, er.. on the grey side of the line!

a 4gb dvd rip is pretty good, but you would struggle to get a nice HD film and sound track in that amount of data... and knowing how slowly the PS3 downloads as opposed to 'other means' of file aquisition I would expect it would be faster to order the Blueray from Play than to wait for a movie to squeeze its way down to the PS3 :)