Aldi - 30L Lumina Microwave / Convection Oven - $149
It doesn't have a well known brand name, but Aldi have a 60 day money back guarantee if your not happy (as long as you have the receipt and packaging), plus this product has a two year warranty if anything should go wrong.
I don't know anyone with a convection oven microwave, but they seem to be growing more popular recently, with people substituting their main ovens for them. They're well over $400, so this seems like a great price, maybe even too cheap...but with the two year warranty you should have no worries.
Here's the features from the Aldi site:
* 30L capacity
* 900W microwave power
* 2000W convection oven power
* Stainless steel housing
* 10 microwave power levels
* Digital timer up to 99 minutes
* Safe child lock
* Chrome finished door handle
* Stylish mirror door
It's in stock from today (8th Oct) until stock runs out.