1: Injection: Liked. Very useful to go along with a patron pool pet or troller/dom pet, or an ally in groups.
2: Dart: Honestly, its a bit -too- good, even with the slightly higher end cost. The animation is a bit sub-par; as someone else already said, using the dart animation from widows as an alternate option would be a great choice to make this look better and I would love that as an option here. Its damage is only slightly better than the competition, but its animation time is half, as well as of a less resisted damage type; while I would only take the other two sets attack powers for style's sake, this dart would be a viable part of the attack chain for some characters(Especially MMs; many MMs starter attacks are weaker than this). This is the only attack power between the three sets I would take and use regularly as-is, even with the bad animation... which, unfortunately, probably means it needs to be nerfed a bit.
3: Speed of Sound: The greatest weakness of super-speed murdered and done away with; by a zero activation time teleport built-in. Unlike the super-jump clone that seems simply superior to superjump, there are actually downsides here in the lack of stealth, but this is a great alternative to super-speed and I can easily see each being a good option for different builds.
4: Corrosive Vial: The damage is good enough for me to use it and take it, better than many epic alternatives, while the recharge is long enough to keep it out of my attack chains. Decent.
5: Adrenal Booster: Not incredible, but highly useful buff; like a mid-grade build-everything-up. Useful in almost every situation, and would definitely take it and slot it for recharge.
Overall; this is a well-built set I could easily see myself taking, and unlike the competition, actually having a use for everything in it on some of my characters. If you leave it the way it is, its probably the set I'll take on any character I'm not specifically building a theme on.