Nah, it's not worth it. None of your pets has any kind of taunt or ability to keep a hold of aggro, and enemies often just keep switching targets.
As such a resistance boost becomes largely pointless, especially since your secondary should be doing the job of protecting your little squad anyway, and the damage bonus Serum gives is nothing short of laughable.
Chairman of the Charity of Pain; accepting donations of blood and guts.
Prophet of the Creamy Truth; "If it's empty, fill it with cream."
They really ought to remove/lighten the crash and make it more offensive than defensive in nature.
Or weaken it a bit and make it AoE, still lightening the crash.
As said, kinda useless (i only had it once, prob the same day i respeced it out again).
Its a mini unstoppable, nice and stuff, but giving your pet the buff and send him in a group of mobs actualy wont help much. Since he is 99% ranged, 1 out of 100 he might hit 2 mobs with any attack he has.
Now if a bruiser of thugs would get this power, that would be fun 
or any melee pet for that mather.
50)Sinergy X/(50)Mika.
(50)MaceX/(50)Encore
Sign the petition, dont let CoH go down! SIGN!
Consider that you can drop a few insps on a pet for the same effect more or less, and then consider what else you can take in it's place. Since you obviously can manage to get 3-4 insps back in 1000 seconds.
You can possibly use it as a placeholder for a -KB IO or something. Or a + 3 def unique. ( Steadfast Protection ) If you for some weird reason got nothing useful to take. Which is rather doubtful.
Rubbish power for ranged pets.
52.5% damage resists for all but Psi for 60 secs.
1.67 End/sec Recovery Bonus for 60 secs. ( 100%)
Mez resists. 60 secs.
7.5% damage buff 60 secs.
7.5% to-hit bonus for 60 secs.
MINUS 16.7 End/sec recovery to target for 20 secs AFTER 60 secs. (1000%)
MINUS 100 endurance to target AFTER 60 secs.
---
Aye it isn't worth taking, comparably to powers such as the zombie soul extraction, thugs gang war and ninja smoke grenade. It is in fact in the same league as usefulness as repair in bots, however I would argue it is MORE useful simply for when your poor little protectors are running out of end, you just boost it up again for them.
I don't know how one would make it better, except to make it have little or no crash, considering i'd use it on my commando anyway who has enudrance problems. Perhaps stacked with Pain bringer it'd make a solid all round tank, but sadly, as has been stated, the commando seems to grab as much aggro as any of the pets.
It really has no place in a purely ranged pet primary.
Serum is weak oob, but it's nice to use on the same pet as you put Infect Henchman on and send him to a group of enemies.
Another usage is to put it on the medic, and send him to center of the battle.
Story arcs: �Viva la Represi�n! (#2327) | Mysterious Virus (#11762) | Four Horsemen of the 2012 Apocalypse (#531874) | Deadly Dragon | White Slime
My story on union.virtueverse.com
First off, yes I chose Mercs...and yes I know they suck, but when you get a theme, name and look in your head and Mercs is the only ones that fit...what ya gunna do?
Anyway, basic want to know how Serum works....sounds like it gives one henchman a dose of Unstoppable, but with the inconsistancy in the Comandos attacks, is actually worth taking?