Gavin, I've owned one for 6+ years but I ride it rarely.
The CT110X (postie bike variation) is not a great tourer unless you plan on cruising at no more than 60kmh (top speed is around 85-90kmh but is not sustinable) - a perfectly adequate speed for most asian countries, but not Australia.
Comfort factor is relative - these are VERY small bikes and you will feel cramped after a short while unles you are 165cm tall, or shorter.
Economy is fine, wind protection is minimal, reliability is so-so because most ex-postie bikes have covered around 30k km and are pretty much worn out in one way or another (mine had very bad shift selection and a totally worn out drivetrain but other components were as new).
The postie bikes also DON'T have the low ratio dual speed box so they don't have the versatility of the genuine CT110s, but they do have an overall stronger frame and running gear as compensation.
It really does depend on where and how you want to ride, but given the long distances between towns in Australia on boring straight roads, I think the speed limitations of a postie bike would become very frustrating, very quickly.
Garry from Oz - powered by Burgman