anyone got one of these and are they worth buying ? How does the sizing come up ?

Before you buy one look at either Onewind Topquilt or a helicon swagman roll, both do the same job but far more uses than the coat you mention.

In reply to Post #2
How many uses does one need for a coat?

Well more than one is a bonus

In reply to Post #3
Liam Gallgher uses his as an extension of his personality