Like what others have said already, I feel that 1plus2 sound signature is on a totally different category so it is hard for me to compare it directly with Roxanne's signature which is in its own category. At the end of the day, it boils down to your own personal sound preference. I have not heard how TH900 sounds like so I cannot help you there.
thanks for extensive review, i deleted large part of this from quote field in order not to take much space.
what puzzled me i was expecting Roxanne to capitalise even more on the already excellent 1p2... so hearing this sounds closer to ASG2 makes me scratch my head.
yes, from my experience ASG2 has closer inner in your head stage. ASG2 is lovely but is totally different animal and that's why i thought about having both of them in future.
but since now you tell Roxanne is closer to ASG2 makes me wonder how much improvement in sound i will be willing to pay? is not ASG2 a golden spot in this case???