I’m using SFML for pretty much everything in my game engine. I started using it to help me learn C++ and never left. It’s pretty amazing; cross-platform, hardware accelerated 2d and one of the best APIs I’ve ever used. It’s a genuine pleasure to work with when it comes to expressiveness and simplicity.
I’ve recently been working on adding rich-text support to my engine, and while SFML does come with text rendering built in, it’s very simplistic. A text instance can only have one color and combination of styles in total, so if want to italicize a single word in a sentence you’re out of luck; you’ll have to split the text up into multiple chunks and position them independently. I’ve written a class that handles this all automatically, along with a simple markup parser to manage formatting. You can get the source here, and discuss it over at the SFML forums on the topic I made for it.
I’ve done some parser work before (notably for Slang), so the markup interpreter was fairly straightforward. All formatting is done with single-character delimiters (*bold*, ~italic~, and _underlined_), and the color tags can contain a hex value or color name. I’m sure it can use some optimizing, but so far it’s quite fast and works exactly as well as the vanilla Text class.
If you haven’t used SFML before, I highly recommend checking it out! The fact that I was able to put all of this together in just one day is a testament to the power and ease of use that it provides.