I'm a big fan of Grid.
I can say much, since I've never toyed around with Vuhdo or Healbot, but from whatever I see on the UI's of guildies I'm always happy I have Grid and Clique for several reasons.
Healbot and VuHDo seem to be really, really direct towards healers, while I have that feeling less with Grid. I use grid on all my toons, on my tank it's nice to see who pulled aggro, or to cast Righteous Defense/BoP on them with clique. Same goes for my mage, I don't see the point of decursive since clique and grid can accomplish the same. And, every character has it's own profile ofcourse, so while my priest her screen is mainly filled with grid, it's smaller on my other characters.