I am located in South Australia and actually bought 2 stelvin cappers from China.
Do they work.Yes they do. Are there any strings attached.Yes there are.
Only buy from an Aliexpress dealer. At least you have a guarantee you will receive a working model. Never ever let the Chinese seller talk you into paying them for CIF transport. If you do when you go to pick the item up you will find an extra transport charge of a few $100. As the docks only allow you 2 days to pick the item up before they start charging you $100 a day storage fee you just have to pay up and try (without success to get a refund on shipping). Use an Australian shipping agent like Smith Chandler to handle all the details.
The manual supplied is in Chinalese so can be a bit of a struggle to work out. But when set up correctly for the bottle it gives a bottle that looks a lot more professional than Nova Twist and at a cheaper price
Once suggestion I would make is to buy a complete spare head (only cost about an extra $50) then if you get breakdowns in the middle of a big bottling run you have a spare head you can pop on right away.
If you need any more info just PM me