As stated in my post about the Nightwing, one of the main reason I went with Eldar for the league was that it would allow me to use my two flyers (or fast skimmers after the rules change). As with the Nightwing the Phoenix was massively overpriced before and now is still expensive but definitely has some firepower.
Unlike the nightwing which SeerKarandras from Craftworld Lansing rightly points out can often be protected by more pressing threats but fortunately it can rely on range a little more as it has multiple 48" range weapons. That is harder to do with something that can move 12 inches and still put out 6 S5 AP3 missiles, 6 S6 Ap5 shots and and still has one more big gun (i'd use either a pulse laser or twin-linked star cannon). The missiles can also be traded in for 6 S4 AP5 that ignore cover, blast templates for a very low price. I'm not sure how I feel about the "upgrade." I didn't take them for the league but they could obviously devastate a unit from 48 inches, especially if you do some tank shocking first.
On the battlefield this guys roll is largely dependent on what he is armed with If it is armed with the blast missiles the role is clearly to hit bunched up units, such as those that just lost their transport, If armed with the AP3 missiles, it is there to force the enemy to use cover as they advance. I prefer the twin starcannon in this scenario, the loss of range isn't so great as it you are shooting at something over 36" away, it probably has cover. Is it worth 225-235 points given that it has the same limits as nightwing and takes up a valuable heavy support choice probably not, but the sheer number of guns it has is amazing.