Hi,
One of the customers were in AIX, the other one I cannot remember (I think it was Linux, if I found it I will mention it here)
There is another one on AIX, but still not productive.
I know another one who has plans, but it might take a little while (things go slow). This one is on HPUX.
The customers I know did not changed platform, used RMAN for the migration to ASM, no compression.
But recently I was discussing with a customer his migration to RAC (still planning phase)
They are changing platforms (Heterogeneous system copy from HPUX to Linux) and we talked about the options to add compression into the scenarios (R3LOAD/GoldenGate/Transportable tablespaces)
Not much information, probably because the features are "General Available" we are not involved in lot of the final part of the implementations.
Hope it helps a little 
Fidel