I'm using IceCap's because that's what was on sale when I ordered mine. If the ARO's had been on sale that week, I would have bought them.
There's a guy on RC (electric130 or something like that) who has both, and he said they perform equally. He posted a picture of the ARO and IceCap side by side, and the ballasts themselves look identical, leading to speculation that they are manufactured by the same company and rebranded for both IceCap and ARO.