What's up with postie bags?

I think its fair to say that the Royal Mail may have tested every bag maker's offerings and then decided that one beat the rest? Therefore its a probably a very strong and durable bag? This bag has been discussed before on this forum. Its a steal if gotten cheaply from a postie, or it can be got for £25.oo from here: http://www.michaellinnell.co.uk/product_info.php?cPath=30&products_id=109&osCsid=2a47f89d2ec322cb0d85b2b9e03a0123

anyone ever used one of these?

http://www.michaellinnell.co.uk/product_info.php?cPath=30&products_id=124&osCsid=2a47f89d2ec322cb0d85b2b9e03a0123

what do you think stupid face!