I've been using Ghost for this blog for about a month (and the ghostium theme for a little less than a month). It works quite well for a lightweight blog, but there have been a few issues that I've come upon.

The Good

• Support for Markdown syntax (including language-whatever code blocks!)
• Relatively lightweight - runs on the smallest Digital Ocean droplet
• (Ghostium) Uses prism.js for smart syntax highlighting.
• Supports blog drafts - I can compose a few posts in advance, save drafts of each.
• Decent tagging functionality - tag posts easily, keeps track of tags I've used in the past and auto-suggests them.
• I control the entire platform to screw it up or make it better.

The Bad

• Language syntax support seems a little finicky to extend. Yes, there's some documentation on how to get prism.js extended, but figuring out how to get that integrated with Ghostium is a bit of a PITA.
• No spell check. I'm writing this in Pastebin because (unlike the native Ghost editor) Pastebin text boxes are fully compatible with Firefox/Chrome integrated spell check engines.