I just wanted to throw out there that the siren and Harpy have now officially come out of Cid and their official rules are here. They seem mostly unchanged since their last CID iteration which is really solid. How are you all going to be using them? I am thinking either a Marshaled Siren in LOD or double harpy on Elara1 in Shadows.
I've dropped a banshee from some of my Ossyan lists for 2 harpies because the points work out the same. having 4 POW 13 shots is better than having 1 POW 14 shot imo, especially on feat turn and when mixed in with future sight so you don't have to burn focus on boosting attack rolls all the time. you do lose melee presence and have to be careful with that thunderbolt if shooting at max range (make sure you've always got at least 2 targets), but overall it's just more shots of only 1 point less power downrange. has worked out pretty well, although right now my LGS is running the mixed CoI themed game league thing that released with CoI so I haven't had a good chance to test it in a regular steamroller scenario yet.
haven't really tried out or even theorycrafted that much with a siren yet. I kinda ignored it in CID because the harpy was just more interesting to me due to flight and haven't really done much with it since.