8 months in and I love Squarespace. Well, I love Squarespace 5 actually. The themes are great, the interface is straightforward and I have integrated Google analytics into the site with no problem. If I wanted to, I could add image galleries and Google Adsense as well.
But the release of Squarespace 6 caused me a problem. It does not work with my favourite blogging application Marsedit. Marsedit is such a good application for blogging for several reasons - ease of image uploading, scheduled posts, multiple blog management and a very approachable developer.
I don't know if this issue will ever be fixed. But until it is, I will stay with v5 of Squarespace. It suits my needs and will be around for the long run according to the site.
Give it a test run by clicking the banner on the right side of this page (shameless affiliate link).
Edit: seems all is not well with Squarespace 6. Some Internet tech nerds are leaving to go to static blogs or back to self-hosted Wordpress setups.