Mu Guardian will heal not just you, but any other pets you have summoned. This can be bad because generally your pets take a larger beating than you do, so they end up getting the bulk of heals. This seems to happen more often than you'd like and at terribly inconvenient times. Like when you're about to die and he's over there healing your imp.
To me, the guardian is more like a stormy with O2 boost than an empath with Heal Other. He's good at patching you up after the battle than an in-the-fight healer.
He has other powers and uses them in a chain that may or may not include his heal, depending on if you're hurt, your pets are hurt, how far away he is, is he in LOS, etc.
So in a nutshell, he's not your go-to guy for heals. If you rely on him to save your bacon, you'll end up in the frying pan alone.
Please buff Ice Control.
Current is right in the aspect of the heals Mu pumps out, he's definitely not your H34Lz0r by a long shot. What he IS good for though, is taking an alpha (he'll die, but you won't, lol), helping keep the aggro off of you alongside your Dom pet, and the Mu pet has the best AoE out of the 4. My dom had one running around with him before I switched to Fire APP.
EDIT: He's pretty versatile as to what you want him to do too, If you want him to pump out damage, slot with a set of Expediant Reinforcements, but if you want him to drain endurance instead, you can slot him with a set of Efficacy Adapter or Perf.shifter. Both are pretty effective with his AoE attacks.
Mmmh that's pretty much what i expected. For the other pets it shouldn't be a problem, planned build is ill/storm and all pets are not targetable, exception for the phantasm but he usually doesn't take much damage. I'll just give it a try i think, the AoE part looks interesting enough at least. 
Dark armor lover.
The Claws/DA Scrapper guide.
Hello dominators
Since we get the patron pools hero side i think i'll get more detailled answers here even if it's for a controller. I was thinking about adding the mu pet to several of my builds, mainly for the healing he can do that seems perfect to replace aid self for some builds (i don't like to rely on random inspirations drops and to be without a way to heal myself).
So, how good is he ? Is it worth slotting him for that ? Can i count on him to keep me alive or does he heal only when he feels like it, as dumb as a pet can be, i guess it would be whenever i'm already full or when i run out of the mission
I'm not too worried about keeping him alive, more about him keeping ME alive, heh. So any info about that pet would be appreciated, as going villain, then coming back, and blow two respecs is a bit too much for a "test".
Thanks in advance
Dark armor lover.
The Claws/DA Scrapper guide.