On the Raptor conversion note: I am not a fan of the current Chaos Raptor models, nor the SM jump packs, so I picked up a bunch of Dark Eldar Scourge wings and used those on standard CSM models. A quick filing/trimming of the top of the backpack mount point allowed me to set these comfortably on the model. I toyed with some adds to this conversion (a jet tube in the center, protruding vents to make the wings look more like power-armor packs) but in the end I liked the clean, stealthy look of the wings by themselves.
On raptor movement: I understand the preference by some for the Rhino filled with CSM option to achieve assault as soon as possible. I field both types of assault units (two raptor squads w/ lesser daemons vs. two rhino squads w/ lesser daemons). I've had mixed results with both, but two things seem consistent:
1. The raptors are faster, namely because of the Run rule but also because they can negotiate terrain obstacles easier than a rhino.
2. The rhino squads are more durable due to the two layers of firing required (rhino has to be destroyed/immobilized first). Unfortunately, I rarely have a rhino arrive at my intended destination, but the overall durability still stands - more models arrive in CC, they just arrive a turn later than the raptors.