They're not legal in the UK. It is legal to have personal amounts of it, as it is in Australia. Personal amounts though, are not what the average user would have at any given time according to the definition of personal amounts.
Should it be classed in the same category as heroin? No. But be aware, it is.
Should they be legal in Australia? Fuck no. Too many idiots, too many school kids with body image issues who will eventually fuck themselves up. It isn't like weed. There is a very fine line between safe use and damaging use.