This logo is ranked lower because it does not elicit much of a feeling from me. The colors are nice and I like circles. I even get a little yin yang out of it but overall it falls flat for me. It needs more personality.
#13 is a definite improvement. It has surely moved from lacking personality to having a clear personality but I'm not sure that it's the right personality yet. If this were a yoga studio, #13 would be in the top ranks.
#13 is difficult for me to comment on because there are a lot of things I like personally about it but I have to remember that those things are not necessarily what this brand needs. So I am trying hard not to confuse the two and to be able to speak clearly for you.
First, I do not think the pinks and purples are right for this. I am finding the orange-reds to be the most fitting.
Second, Pilates is more about moving than meditating. #13 evokes more of the latter. The image needs to incorporate more movement.