I've released version 0.5.2 of the aptitude package manager (release notes). You can download it from Debian's experimental archive, or from the aptitude package page.
WARNING: This is an unfinished piece of software. Do not install it if you want a package manager that does everything you need perfectly all the time. It is buggy and incomplete.
This update includes major changes to the resolver backend and a new and improved GUI frontend for the resolver:
It also includes an assortment of other fixes and improvements. Click through to the release notes to see a list of what changed in this release, with screen-shots.