I've recently switched away from a two-computer desktop (Linux workstation with a Mac laptop on the side), to a single Mac laptop with multiple monitors. As part of the transition, I've been looking into the new possibilities for my primary code editor on OS X coming from Ubuntu. I primarily write PHP code, and am frequently working on Drupal modules. Here's a list of some of the apps I've been evaluating:
Komodo Edit (Free)
My longtime favorite, which I've been using as my primary code editor for the last 7 years.
Pros: cross platform, free, autocomplete, code hints, extendable, New Source Tree sidebar module.
Cons: Some display bugs with multiple monitors make the autocomplete and lookup popups appear on the wrong desktop, autocomplete not working
Some of the bugs I'm seeing while using Komodo Edit on my new machine may be configuration errors on my part, but the popups appearing on the wrong monitor are a known issue. I have a feeling I may end up coming back around to Komodo Edit eventually, just because it's so familiar and it does the things I need so well.
Coda ($75 in the App Store)
Coda comes from Panic software, creators of high quality OS X software. Aimed primarily at the Web Development audience, Coda looks great and makes it easy to work on a remote set of files.
Pros: native OS X interface, clear grouping of projects into "sites", custom autocomplete, extendable with plugins
Cons: price, autocomplete is local to current file only
Coda is very easy on the eyes, I just wish it was easier to get site-wide autocomplete with hints. I need to be able to call custom functions from one drupal module to another without having to open the file and copy the function name.
Sublime Text ($70)
Sublime Text is my current goto for code editing, is a strong favorite for OS X developers and has a great feature set.
Pros: Extensive and powerful keyboard shortcuts to get around your code quickly, edit multiple selections simultaneously (e.g. change all instances of a variable name to another name on the fly), large selection of packages for extention
Cons: bit of a steep learning curve for keyboard commands and package installation. Only local autocomplete
I'm still learning how to get around in Sublime Text, but I'm optimistic that I'll be able to get it to do the things that I want it to with a bit of time and experimentation with some of the custom packages. While it does cost $70 to register, there's no set limit on an evaluation copy, so go give it a try.
Komodo Edit: http://komodoide.com/komodo-edit/
Sublime Text: http://www.sublimetext.com/