I would have given this 5 stars as it's a great way to see the scale of Kakadu. However, we had 30min of sitting in a flying sauna. It was so bad that neither my partner (who has done lots of small aircraft trips for his work) nor I (never suffered from travel/ motion sickness of any kind, not even in smaller aircraft) could look at the scenery for more than a moment every few minutes. Instead we had to spend most of it looking at the horizon. The heat made us both feel extremely ill - along with other passengers, one of which made use of the special bags.
If you can be assured that you'll have air con during the flight, do it. It's an interesting place and you can see some of the land formations that can only really be appreciated from above. If you can't get air con, avoid this unless you absolutely love to be drenched in sweat in a tiny space.