I have an Advantium wall oven (240 V) purchased  in 1999 after seeing it at a Home Show in Portland Oregon.  Since I don't have a double oven, it comes in very handy and fills the 2nd oven gap for me.  I use it frequently on a daily basis and during the holiday season it works over time.  I have recommended it to a number of friends.  
Unfortunately, some of the paint on the inside of the door is starting to flake off.  Other than that, it  has been working trouble free for quite a few years.  I find it a real time saver and it is easy to keep clean.  Wouldn't want to live without it.