This release was mostly focused on performance and memory optimizations.
On the performance front, the major focus was on start up (i.e.: start up Eclipse, open an editor, request a code-completion and show the globals token browser (Ctrl+Shift+T)) -- which should've become pretty fast (tested only with the Eclipse runtime and PyDev -- as things in other plugins can't really be controlled -- the subversive plugin for subversion seems to be especially slow to startup).
Memory-wise, things have been improved too, with the AST taking up less memory and doing a 'pseudo-intern' for some rather large caches (it's a pseudo-intern because the String.intern() function is not used: a HashMap is done and strings are reused inside it for some processes -- and later that HashMap is thrown away), and the Jython plugin was fine tuned to make less plugins visible to save on memory (and startup time).
Just to note: the real memory used can be seen going to window > preferences > general > show heap status (the real size of the java process in the OS will probably be bigger as java will usually grow to the size specified by -Xmx, regardless of how memory it's really using at a given time). Personally, on large projects I allocate 300 Mb for the process, but this is mostly because the subversion plugin seems to be rather resource hungry -- migrating to git on some of those projects seems to be making things better :)
Aside from that, this time I spent some time migrating the PyDev homepage to a wiki ( https://wiki.appcelerator.org/display/tis/Python+Development ) -- right now it's not available for external edition, but that should happen soon (hopefully), and the idea is that the PyDev homepage will be generated mostly from that wiki.
And as usual, a bunch of bugs were fixed :P