Pros

First text editor I've seen that feels designed for usability and reduces - rather than increases - the amount of arbitrary commands and strings of text I need to memorise with slick, well designed autocompletes, menus, etc.
Awesome, ingenious tools for effortlessly finding your way around large complex files and making multiple changes at a time.
Snippets, bundles, regex find/replace, etc are all supported and there's loads of potential to extend and personalise it.
It also feels lightweight. I've never liked big, clunky IDEs, and despite having many handy features most IDEs lack, this feels as light, fast and responsive as the lightest text editors I've used.

Sublime 2 beta is even better and stable enough to use, and the developers seem highly active and responsive.
It's reassuring to know that there are versions for Windows, Mac and Linux, and that there's a portable version.
(it looks stunning too! It's simply pleasant to use)

Cons

It's not actually free, only the evaluation version is free. I'd say it's easily worth the money for the time it'll save - it's pretty cheap and pays for itself extremely quickly - but it is misleading that they list it as 'free'.

Also Sublime 1 isn't nearly as good as Sublime 2 beta and Sublime 2 beta has crashed on me a couple of times - not much more frequently than any other text editor I've used, but if you use the beta (which I do recommend) do be aware that it's (as of Feb 2012) decently stable, rather than highly stable - so save often just in case.

Summary

They say there are as many text editors as types of developer: Sublime Text is for you if you want to spend less time and brain power doing repetitive tasks and memorising arbitrary strings, commands and incidental facts about your code's structure, and you want to focus as much of your mental energy on the design process of coming up with and creating features and functionality.

I guess you could describe it as Textmate/E Text Editor crossed with very good best practise UI design.

For me, it represents the exact opposite of that masochistic hardcore programmer's attitude satirised in the xkcd butterflies cartoon - and I love it.