Yes, it isn't 0.4, because some things are missing. Main issue: it's slow with large files, but it is fixed (the problem is with merging the changes back to head...)
From the news:
- syntax highlighting for records and macros;
- go to included file;
- goto definition of remote and local functions;
- increased stability
If you use it and want to give feedback, the easiest is probably to go to Window->Preferences->Erlang and there are links to SF's issue trackers.