The governor said:
Has any one had any bad experiences with Unallocated in the buying and selling ???
No - been using this service since August 2015 and have nothing but praise for it. Customer service has been pretty good, too.
Hindsight and all that..but it was possible to take physical possession of kilo Ag in December 2015 at something like AUD 660 using this service (ok, provided actually getting to the Perth Mint to pick up then didn't present an issue or cost extra)
As far as coins go, my understanding is that after paying extra to go from Unallocated or Pool, Allocated to Allocated and arranging delivery you'd end up with whatever 1 oz Kookaburras happened to be available to fill your order, ie you can't specify any type of coin that you would like ("jeez, mate" [there was an administrative oversight for a couple of years on the order form relating to 2oz Kookaburra coins ..... but that has since been cleared up])
Bron has also already stated that Unallocated Au (which attracts zero storage fees currently) won't be around for ever.
Personally I find it hard to go past this service in terms of price, convenience and minimisation of counterparty risk - if anything in the reverse order. That means that buying or selling, the Perth Mint holds up their end of the deal when you want, at their price. In effect Perth Mint adds around 31 cents to the spot price when you buy Pool, Allocated silver.
Is that a bad experience/good deal ? Depends on your perspective.