Painted Succubus. How would I play it?

There she is. I liked the Dark Elf Sorceress, and I thought she fitted well into the corsair theme of the new paintscheme. She isn't a gladiator, but a female piratelord. I chose to get this model so that I would have more choices with HQs. The 1850 list I've been throwing around lately needs 30 points for a fourth trueborn in one of the squads. I could get that by cutting the Baron. Anyway, I feel exploring all the different choices is a good idea. I could go with a haemoculus, but that maybe adds the least. A blasterchon is ok, I tried that out, but since I'm exploring all options I'm also gonna try the Succubus.

The traditional setup is with an agoniser. 85 points is pretty cheap for a girl with lots of high ws and ini attacks. 4+ invul adds survivability against basic troops. However, I don't have the points for that. What I'm looking for is a cleanup lady (similar to my wyches), but who can also joins squads (reavers and wyches) to add a cc boost.

The Venom blade is nice for 5 points, but I got my eyes on razorflails. 10 points and weaker average of wounds against t4, but smaller deviation. The razorflail has rerolls and isn't so prone to failing horribly due to badd to hit rolls. The razorflails are a sure investment. This is a difficult decision, but atm I'm leaning for the razorflails. Dark Eldar are brittle and I need to know that the Succubus doesn't fail horribly right when I most direly need her. The venom blade's advantage isn't much against 3+ marines, so for I'm gonna try the flails first.