I've been using Squarespace to publish my blog for a couple of months now, kind of on a trial basis to see if I liked it enough to permanently move over from Typepad, which I've been using since 2004.
I really, really like it. Even though I've had to re-learn a few commands and get used to a totally different publishing interface, I find the service overall intuitive and fun to use, and the themes look good.
Speaking of themes, mine was custom made by Krystyn Heide, Squarespace Design Architect who does fantastic work (she's the brilliant mind behind my buddy Kevin Pereira's blog, among others). Not only do I think Krystyn is extremely talented, but she put up with my non-designer ass for about a month while I hemmed and hawed about where my search bar should go (I'm not kidding, I changed it about 12 times... in 2 days. If I were her I would have dumped me so hard). So, a huge thank you to Krystyn! You can check out her custom designs and learn more about her here.
Everyone else at Squarespace has been wonderful and has made my transition as smooth as possible. If you're looking for a good blog host/engine, Squarespace has my vote.
And now, back to Christmas shopping...