Reapers kill them as fast as they do normal marines, and dire avengers work well too, as you can kite outside of rapid fire range. Dire avengers can also be very efficient against tzaangor and cultist blobs, as can swooping hawks with doom support. I've done well with linked-fire fire prisms lately, as they struggle with anti-tank, and they can kill or severely deplete 5 man terminator and 10 man rubric squads using the strategem.
A demon prince can definitely cause trouble, but even though he can't be targeted through normal means, he can still be held in check by the restrain power or shot at by rangers, Illic, or a reaper autarch with mark of the incomparable hunter. Use all 4 of those things and you just may be able to drop him without him making it into cc.
Hemlocks are also very good, as they hit hard and can potentially position themselves so that the DP is targetable. They also give you an extra deny that comes in handy against Thousand Sons. The morale debuff can help significantly as well, causing rubric squads to start taking morale checks after only 1 casualty.