I'd say the only way to do it is load them up in a Raven (two squads of 5) and get up in the enemy's face Turn 1. Gets around chaff/screening issues, and the Raven itself is superb at cracking open transports/clearing a landing zone with hurricanes and assault cannon. Just hope nothing with Fly or dedicated anti-air knocks your Raven out.
Turn 2 you hop out 3" before the Raven moves, go another 6" into enemy lines, make sure you land a Brother-Captain nearby either with 'Gate' or Teleport Strike (you could even shove him in the Raven itself if you are brave). At that point you're pretty much going to cast onto whatever is 6" from the Purifiers (conga line the squads so you have options, you might BTFO your initial target). Double cast 'Purifying Flame', delete a character or badly injure a superheavy/monster (save your re-roll strategem for the D6 mortal wounds). Throw in a 'Vortex' from the Brother-Captain for good measure, then shoot+charge something nearby.
I think in terms of getting the unit to its target destination, you're absolutely right. The Raven is the perfect vehicle for the job. I've used it to fairly devastating effect myself, except without the Vortex Bro-Captain.
As to the cost: Strikes are certainly good, and they're an efficient choice for us right now, but I wouldn't make claims to their having a higher damage output (which is what I tend towards maximizing). I can't deny that Strikes' being able to Teleport means you have more flexibility in list building because you don't pay a transport tax, but if you're willing to restrict your list and playstyle a bit, I think Purifiers are well worth the cost.