We initially checked out Ohya about a year ago, since it was close to our place in Desert Ridge at the time. We have since gone back a few times for the BBQ sets, and a little Sushi.
On our last visit we discovered they now have a BBQ/Sushi Buffet. It's well worth the $26 per person for all you can eat Korean BBQ and Sushi. They do have a somewhat fixed menu of items that you can order from at different price points. However, at the $26 price point you get a lot of variety of meats and sushi to pick from.
Our server Simon was a bit soft, but had the personality to really make it work for him. He did an awesome with our constant ordering, and made us feel right at home.
We love this place, and will definitely be back!