Use both? You can't really compare Aid Other and Triage Beacon as they are two different things - it's like comparing endurance drain and damage.
Triage Beacon is best taken post-L20 when it can be slotted with SO's/IO's to an effective level of regen.
Aid Other is best taken as soon as you have an available slot for it - much like FF, Traps Masterminds benefit with another heal on hand.
Triage i only find usefull if u fight for longer time on a static spot. Like the invasions is good example. However often u just rush to each new group, perhaps sticking 20sec max at a static spot.
I dropped it eventualy, those 3-4 little fights it makes good use doesnt compensate the somewhat longish recharge.
50)Sinergy X/(50)Mika.
(50)MaceX/(50)Encore
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I took TB at level 4 because there was nothing better to take. Then I took Aid Other at level 8...
Both are decent. Triage is invaluable on a ranged primary like Bots (or Mercs) when you have all seven henchies summoned and you know you're about to have a tough fight on your hands against multiple enemies. Since TB is an AoE it gets better the more toons/henchies it affects... it really increases the survivability of your pets, since combined with Poison Trap and FFG the +regen helps them last much, much longer.
Aid Other is useful when you just want to top up the HP of one henchie, I find it's especially useful just after my tier 3 weathers an alpha strike or when I'm fighting against bosses which do single-target damage.
And you can even use them both to heal other villains, if for some reason the mood should take you... 
Wouldn't dream of not having TB on my bots mm. But bots are good in that way, they stay stuck in one place until the fight is over. I also tend to solo mostly on my bots, since it's on Onion! 
As a team power it is fairly useless mostly since most fights are over fast. but if you're like me, you enjoy 8 man relentless fighting and that means AVs etc, and that means long (erhm, well, not really) static fights where the team does value a TB. So far I have not seen the need for aid others due to my good protector bots, the FF and well behaving pets that stay put. On occations I've dropped a heal insp on my assault bot.
But as MZ said... don't consider TB as a heal power... It's more like a second force field negating the dam made. It's +regen, not heal. So, as usual it's back to: How do YOU play? I haven't tried mercs but they seem to behave pretty much like bots (and yet not at all like bots).
I'd hang on to TB anyway, since you can always slot it with regen tissue/numina unique to become something as silly as a regen MM, sort of, but not at all.. kind of...
After returning to the game for the first time since I7 a few weeks ago I have only just dusted down my MM to get him levelling ready for the RWZ (currently almost L33)
He is merc/traps. I find that Triage Beacon really doesn't help in keeping my troops alive due to burst damage. The medic is next to useless. I am considering Aid Other.
Just wondered about what other /traps MMs do with regard to healing the minions.