Borehole is a rather mediocre attacker, but it's not bad. It's easily viable in base set, but worse than most other random set attackers, so it probably won't be our main attacker this set. That said it's still a pretty good thing to open with because of the vigilant absorb it provides; it both forces out a Wall and relieves you from the need to buy a Wall against your opponent's first attacker.
Redeemer used to be a fairly strong attacker that could often be the core of your strategy until it got nerfed hard in a balance patch. It's mostly only worth buying if you're already on green-blue.
Bloodrager is also a very strong attacker, but only in some ways. It's very adept at countering large absorbers or lifespan defense, and is therefore well-suited to rushing down an opponent going for a big economy and trying to hide behind an Energy Matrix or something. However, there is no red support to protect Bloodrager in this set, so I doubt a red rush will survive the pressure of Redeemers and Boreholes. Definitely not when you add in Fission Turret (see below).
A very efficient green-sink and source of burst damage. Actually, this unit alone is probably enough to stomp Bloodrager in this set - massing Conduits and saving the green until you can buy enough Cluster Bolts to force a breach can actually be a legit strategy as a counter to red rush. Other than that though, Cluster Bolt isn't usually a high-impact unit. It mostly serves as a combo with other burst damage or as breachproof support, etc. But wait. This set has a combo for it.
Fission Turret is a pretty good unit without its click ability. When you do click it, you normally have trouble spending all the green efficiently, but Cluster Bolt puts an end to that problem. When you click Fission Turret and are able to spend all three green on something good, the unit is more efficient than Hellhound. And costs 4G. Talk about a combo...
Nivo Charge is one of the most brutal pressure units in the game. Now this is a genuine counter to Redeemer. Buying a Redeemer already places you under serious pressure on the Gauss Charge turn; adding two Nivos to that makes it all but impossible to defend. Especially if you can synchronize a Nivo Charge or two with a Cluster Bolt turn, your opponent had better watch out. This game is probably going to fast and brutal. There are still two more units to consider though.
A big absorber is normally what you look for to rule out a rush. For a 6 HP absorber, though, Omega Splitter is actually incredibly bad at countering rushes. It's clunky, high-tech and non-prompt, which makes it somewhat hard to get out while being rushed, and when you do get it out it'll probably be on a mere 15-16 Drones - you had to go for absorb quickly since your opponent went for attack quickly. That means you can't really afford any more tech, so you're basically stuck on spamming Omegas for the rest of the game (note that this means your opponent can buy Redeemer safely). While Omega is a reasonably efficient attacker, it also takes all your resources every turn when you rush it like that, which means it won't be long before you can't buy them anymore. Also, Omega gets the majority of its power from absorbing, but if your opponent buys two Nivo Charges then you can't absorb on Omega because they'll freeze it. There probably isn't any other way to defend on that turn either since you don't have a leftover Wall to start with and they probably bought a Cluster Bolt too. So yeah, Omega isn't happening this set.
The Wincer is actually a very strong unit, but there's no way it's coming out here for basically the same reasons as Omega. It forces you on 2 Blastforges and an Animus, which is probably worse than 3 Blastforges, and your opponent can defend the first shot because they're on green-blue tech, and there's no way you're holding out long enough to fire a second shot. So The Wincer is also a bad idea.
So there's my thoughts on this set. Go for a fast Conduit, buy a Fission Turret every turn if possible, click dying Fission Turrets if at all possible, and avoid Redeemer in a mirror match because it's too vulnerable to Cluster + double Nivo burst. Borehole should probably be the go-to purchase if you have blue that isn't needed for defense, but Redeemer might be better if your opponent goes for Omega or Bloodrager.