There is a new version of M2E, now part of the main eclipse project. Among other things, they claim that it can now handle nested projects, one of the biggest missing features. I haven’t tried this feature myself yet. Earlier versions of m2eclipse were (deservedly) much-maligned. But it has been in active development for the past couple of years and it’s a pretty nice tool – get it even if you use it for nothing more than the POM editor.
Install it by searching for m2e in the eclipse marketplace or using this update site: