They are both good guide cameras. Duncan has the Orion, I have the QHY5 - and I haven't has a problem with mine either. I would go on price. The Orion Star Shoot Autoguide is $459 at
Bintel
The QHY5 is cheaper $380 at
myastroshop.
Also note Orion won't ship products to Australia - you have to go through a local distributor usually. I see the attraction of the kit from telescope.com, but if you call one of the Australian retailers, they are all very helpful and they can help you put all the pieces together. I think it's best to do this over the phone (not email) to to make sure you get all the stuff you need and don't buy things that don't fit or won't work with your existing gear.
Just found
this link too.