I just finish listening to 'PM's Love theme' from Love Actually O.S.T., going forward and back b/w RE0, TF10 and SE530. This particular performance is a mix of orchestra and electronic instruments, quite suited for demonstrating the strengths and weaknesses b/w these three IEM.
For RE0, it feels like the performance is taking place in a large, open top stadium while I am sitting just a few feet away. Yes the drum is placed slightly too far away to give me the heart pounding effect and I am sitting too close to the performers to have a proper sense of space, but I can clearly tell the sound from each row of instruments, like they have all been placed in different layers of their own.
For TF10, it feels like the performance is taking place in a mid sized concert hall while I am sitting in the first few rows. I can feel the sound bouncing around the wall giving the sense of airiness but the layers of instruments are no longer clearly distinguishable. The finest of the detail seems to get absorbed by the distance and the wall.
For SE530, it feels like the performance is taking place in small school hall and I am in the middle of the room. At first everything seems fine but when the drum and all the other instruments start kicking in, any sense of space is quickly overwhelmed and all the sound seems to get meshed together.
For this piece of music, I think RE0 is showing its best - but don't confuse RE0 to be universally best. TF10 is still more balanced sounding and SE530 is still great with vocal. The point is, even with the relatively low price of RE0 now, you should know what kind of sound signature you like first. Buying gear w/o regard to your own taste is just a waste of time and money. More than often, sound quality is in the ears of the beholder.