When it comes to the whole "Sexy Monsters", for me themselves arn't the issue, but how they're incorperated.
Raven Twins - Interesting idea, but absolutely a waste of characters since as far as I recall they just had a cameo in Trapped in the Walls which made no sense.
House of Vayne - I loved pretty much everything about this concept, though I wish they had their own unique house. Though admittedly, they had cameos in Taste of Blood which was vampire themed so it was a better fit then the Raven Twins, that and they did have the little runway show.
My X - They were on the right track with having a unique house for the icon, even though the house was nothing to write home about. However I will say they were really clever by having the My X concert since that did a bang up job at incorperating the icon into the event, admittedly more so then other icons the event has had.
Now for Ms. Scarlett, she feels tossed in at the last moment so I'm expecting she'll be relevent only to her house and nothing else. I think the only reason she's the face of things is because she's the only new thing the event is offering this year.