OK, so it's not pretty, but it is free, and it includes most of the features power users would consider to be the bare essentials: code colouring and a handy live preview function that updates - albeit with a slight lag - as you continue to type.
The ugly interface is probably explained by the fact that the system requirement demand Mac OS X 10.2.
It has a slightly Java feel to it (although it's a native application), with bulky drop-down menus and a send-to-browser feature than we couldn't get to work. Neither could we get the Quick Insert feature to drop in any international characters, leaving us wondering whether Leopard was an operating system upgrade too far.
If all you want is a quick and easy tool through which to write code, you could do worse than opt for HTML Edit and do it all by hand. Compare it to TextWrangler, though, and you'll see you could also do much better.
Our advice would be to keep it in your Applications folder for absolute emergencies when you need a cut-down editor, but not to rely on it for industrial-strength editing tasks.