There must be several post from me on these things??
Anyway, I'm not busy and I have used both and still use them. I've got a custom CTi2 and after lots of back to back testing I've gone back to using this brace, for now.
I think they are both very similar, but the Donjoy I have is the Armor model
www.djoglobal.com/products/donjoy/armor and its proven to be not quite as well suited to use in salt water as the CTi.
My Donjoy has a fair amount of rust on the buckles that hold the velcro straps. Otherwise is is in good order after more than a years use.
My first CTi lasted 3+ years, a long time IMO as I used it quite a lot, I called the distributor about a third set of replacement straps and in the conversation I mentioned that parts of the surface finish original brace had cracked. The importer asked me to send it back as it sounded like "delamination" and this was covered by warranty. In the meantime I purchased a Donjoy. Around 5 weeks later I was sent a brand new CTi brace, which I was very stoked about!!
I travel with the Ci because it is carbon, lighter and nicer to wear for longer periods of time. I think the Donjoy design is stronger and provides more support and if I spent more time customising its shape it would be equally comfortable. I've noticed now that Donjoy have a more advanced model and they offer it in a custom option.
I needed a custom due to the original injury and the way that it has changed the shape of my leg beyond what an off the shelf brace will adjust for.
Gall Bros medical is the importer and distributor of CTi in Australia
gallbrosmedical.com.au/Donjoy seem to work through independent distributors in Australia, who I imagine make a healthy commission or markup on each brace they sell. The person that sold me mine was a qualified physiotherapist, that visited me, and later delivered the brace and made sure I knew how to fit it properly, I was very happy with their service.
I've been warned about wearing the braces for long periods of time due to tightness of the straps and the risk of thrombosis/clots, but have never had an issue with this.