The feature that kept me on Aptana the longest (I now use vim, which I would not recommend to anyone - and damn this survey for making me lie despite my extensive experience with Aptana - ) was the formatter.
With a simple, CTRL+Shift+F - your code is perfectly indented, formatted - and mostly PSR compliant (it is good for Ruby, also -)
The customization surrounding the syntax highlighting was also wonderful - and Auto-Upload is great, as well.
I have converted many DreamWeaver users to this - and they tell me that while they can easily afford DW - they prefer Aptana for various reasons (which I couldn't recount)
A feature I still have not been able to replicate flawlessly in my new IDE of choice is the documentation tooltips -
If you double-click on any given function, you immediately get the documentation for it -
In fact, simply defining a function, and putting the proper /** docblock with @specs */ before it would also give you access to whatever you wrote in your @docblock -
Git integration - the git-bash that comes with it - are also wonderful, highly useful features -
The Outline feature also proved plenty handy, but the right folding mechanism and proper search-hotkeys make this a feature that I don't miss.
All in all - Aptana is Eclipse -
So, if you learn to use Aptana - you're learning to use Eclipse - and this can prepare you for jumping to another Eclipse-based IDE in the future -
So! When you move to a new language, you have familiar tools that follow ! This greatly aids with the learning curve of a new language - - - -
The fact that it is powered by Java is the worst.
I never had any problems with Aptana - I only ever had problems with Java - (which, of course, can be fixed by tweaking the right .ini file - but who has time for that !?)
Otherwise, some of the other features are a bit less intuitive - such as connecting the thing to xdebug - and sometimes, it can be a pain to add the remote host -
(Imagine you have multiple projects on the same server, but you have to reconfigure the remote host in the same way for each project - even though it should be a simple drop-down menu with an input for path)
Aptana is free -
Aptana is better than DW -
We saved money - we saved time in debugging -
And our code looked clean and pristine (and mostly consistent amongst teammates) because of the formatter -