Hi
I can confirm it is still available though hard to find. They were selling cans of it for $25 at the Sydney Caravan and Camping show this week. Can't remember which one of the stores had it.
The difference between the 424 model and the 414 model is that the 424 model is physically much smaller than the 414 model which is an advantage if space is at a premium. I suspect however that the 424 model is currently not available in Australia as it is not listed on the Coleman web site.
Regards
Allan