I've been using Squarespace 5 for many years now, both for my own content, as well as having built many sites for clients who wanted to use SS5. My own site was a portfolio site, where I got to really express my web design aesthetic (featured as an example site on Squarespace for many years), but I'd also built many straight forward websites for small to medium sized companies on SS5. While not a CSS Jedi, I could definitely make SS5 do what I wanted it do, well beyond the standard templates and styling controls.
Do I still recommend Squarespace?
Yes. Sort of... kinda. However, I am no longer a Squarespace evangelist. I used to be all, "WHY ARE YOU NOT ON SQUARESPACE? YOU SHOULD TOTALLY BE ON SQUARESPACE! I'M ON SQUARESPACE! I LOVE IT YOU SHOULD TO YADA YADA YADA..."
Things I love: The new templates are amazing. The index page is super slick -- I LOVE THAT. Some of the new behaviors and general organizing tools for dynamic web content border on genius. Handling of photos and video seems greatly improved. E-commerce is a massive addition I've been wanting for years! The iPad portfolio app is pretty brilliant. And the UI and overall design for this platform still blows my mind -- best I've seen.
So why have I cooled on Squarespace? It's not any one thing, but in aggregate, I'm left feeling frustrated because I can no longer make Squarespace do what I want it to do, in a predictable fashion. Yes, sometimes a little common sense CSS will do the trick. Other times, it's a glaring, maddening, "how the hell did this pass QA?" feature hole in an unfinished product. Other times it's just an obvious bug that needs fixing. It's the unpredictability that really bothers me.
I usually end getting it to do 70% of what I want it to do, then log a ticket and wait for an update. Test the update, and hope things work out. If it doesn't work out, then I have to rethink my design, or figure out some other work around. If I can't find a work around, I log a feature request, light a candle and begin vigil to see if it makes a future release.
I'm still here. I haven't left. I thing we can work things out. I think SS6 will recover, and mature into the partner I used to worship. We'll see.