ive just done mine,
well almost,
is it worth it, yes it is,
i bought mine from ebay and it looks much harder wearing that protecktacote, it makes a brand new layer rather than just covering the floor,
it takes a little bit of getting use to when applying it, i would take a weekend to do it if i did it again, but for around £60 to do a transit van its pretty good
my dad fiberglassed his roof 20years ago and it is still going strong, much better than felt, and it an van you can build up the sides so making a valley as it where and a draining point for reels etc etc if you want