ratty, it takes all sorts. In some circles the old H mask was prefered but I understand the S10 or, for the more extreme, the AR5 is much sought after. Similarly I have heard that the early Mk 1 NBC suits with their exposed charcoal were a f***** item.
G-trousers and pressure jerkins are more difficult to come by as well. To think we got trussed in this kit for work