Been waiting for our new GE Profile PT9800SHSS for a while.  We replaced a 16 year old GE Profile UJT965SF4SS combo wall oven with the new Combo with convection & Advantium technology.  Too new to have many valid comments.  Last night I made 2 huge baked potatoes in the microwave.  To my surprise they were cooked completely throught.  No hard, uncooked spots and they were HUGE potatoes!  I've also ran several meats through the defrost and they were great, not cooked, just defrosted.  On the lower oven, I've cooked several frozen prepared entrees.  Both turned out great.  
I find the ovens to be intuitive and accurate.  It is a beautiful appliance.  Like the other reviewers, I find the kitchen timer signal to be quite faint as it can't be heard outside of the kitchen.