We have had ours done there many times. The quality is excellent and the photographers are very good. I have liked the backgrounds and props as well. They take about 2 weeks to get back.
They are pretty expensive, but sometimes there are coupons on their website, and you can get a card so once you spend a certain amount, you get the next set of pictures half off.
At our last sitting, they took 5 poses - I had them do one of each kid separately and three of them together. Only one of them together turned out because there was a "light leak" in the middle of one of the pictures and eyes were closed in another.
One thing I really don't like about them (and I don't know if it is like that at all Olan Mills studios) is that you do not have a chance to look at the pictures and order the poses and sizes you like of each one. They develop a certain amount of each pose and you buy the ones you like. If you want to order extras, they cost considerably more. And it is really hard to leave pictures of your kids behind, no matter how much you like them.
Our Olan Mills is located in our K-Mart store. Every week they select a picture of the week to display at the studio. My girls' pictures have been selected twice, which they thought was really cool. So did I since you get a free big picture.
Hope you get nice pictures!
Denae