Optus are offering the the latest iPad 32gb LTE for $0 p/month on their $35 plan.
You get 10gb of data a month and music streaming isn't included in your data usage.
Assuming you buy the tablet at RRP ($669) you are effectively getting 10gb of data for $7 p/month.
The 128gb version is available for $5 p/month more.
There is a really noticeable difference between the screens of the Air 2/iPad Pro 9.7 when you have them on next to the new iPad. I have found the screen to definitely be inferior.
I only ordered the newer model for my son as he wanted more storage (128GB vs. 64GB he has on his Air 2), but we ended up returning the new iPad and sticking with the Air 2. I would of given him my iPad Pro 9.7 4G model since it hasnt been used in months, but it only has 32GB storage.
Anyway, hope that helps.