Wasted quite a few hours today trying to get a Vala/Genie IDE working.
VTG is basically broken, crashing at random. It had problems before this; having a fairly rigid concept of a "project", not supporting non-autotools build systems or libraries very easily, not supporting Genie, and the symbol mapping having odd quirks, so this is not a huge loss.
A newer Vala plugin for gEdit, Valencia, looks promising but doesn't support recent Vala versions and attempting to build it raised pages of errors.
Anjuta has always looked interesting, but I've never managed to get the Anjuta Vala plugin to compile. At present, it doesn't appear to work with Gnome 2.28.
I don't use Eclipse or Mono, so the final option is Valide. To my surprise, it's been packaged for Ubuntu and works out of the box. It supports Genie, it seems to have features on-par with VTG and the other IDEs, and works with the latest version of Vala.
My only complaint so far is the new project wizard doesn't list the AGPLv3 as a license option, but then none of the Vala IDE options do yet.