When Android is happy with 2GB RAM, iOS will soar on 1GB and WP8 on 512MB.
Here is what the IP numbers mean. http://sourcetech411.com/2013/04/understanding-the-ip67-rating-for-waterproof-cables-and-connectors/ I know that some Samsungs were IP67 certified, about a year ago.
No clue what when Android is happy means. Both the 1020 and Icon flagships have 2 GB ram BTW, same as Android flagships. That 3gb ram on rhe Z2 is justified by 4k processing.
And the Z2 is IP58, not IP67.