Yes it is.
I am a Shopify Expert on the marketing panel. I have clients that ask me this question every other day at least. So much in fact that I ended up just creating a White Paper to refer clients to so that I don't have to repeat myself over and over again. If you are curious about what makes Shopify SEO friendly then you can check out the White Paper at http://www.denverseo.bz/is-shopify-good-for-seo.html.
I hope that this helps clear up this issue for anyone that might have questions about Shopify and SEO.
From what I have found you can really optimize any platform well, it just really depends upon who is in the driver's seat, their previous experience, and how talented they are when optimizing websites.
Cheers,
Martin
