Not only is does this app lag and have several technical problems that should be worked out, its hardly better than the free version for the average customer. If you are not into inversions and other advanced yoga poses, you should stick with the free version. It has everything you need in terms of basics and was, in my opinion, a very good app. I mistakenly thought that a good app could only be made better, so I purchased Pro and have since deleted it from my iPod because I was unsatisfied. It was definitely a waste of money.
I gave it two stars instead of one because it does actually provide a good array of asanas and tells you some things about the history and true purposes of yoga. However, the free version does the same thing.