We have a Wix site but I wonder if we would be better suited with square space

[SammisBest]

Our SEO has taken a hit in moving our website from homestead website builder to Wix this last year. 1,500 unique visitors a month to 400 on our website www.bestlifeint.com using much of the same SEO and content. I think 2 of our main issues now (site speed and SEO friendliness) would be addressed in the switch to squarespace. But I guess is it worth it? I do not think google likes the whole hash bang html5 ajax thing wix uses and our website relies heavily on good seo. Any advice? I am starting link building but it might be a waste if we switched the site and in turn changed all the page url's as wix uses ?! for it's pages. Just need some clarification ideas on getting traffic to our website, also SEO MOZ software is hard to use report card with wix. We also switched our ecommerce from homestead to shopify and this has been a good move. Shopify (our ecommerce actually gets more traffic than our website now. But the problem I feel is wix hurts our seo just by being on their platform. Seriously thinking of squarespace but feel we would have to start from scratch and just match some of the elements on current site. Any insight, ideas? Am I on the right path in my thinking? Should I just stick it out with Wix?

Thanks. -Brian