I agree. The green split does look a bit...retro?...ugly? However, I LOVE the blue and red colour scheme. It's just so unique!
After about 30 hours of break-in, the difference between the ER6i and the ER4P are almost immediately apparent after a quick A/B. I used a very well recorded, but lesser known recording of Schubert Octet played by the Camerata Freden Octet. The ER6i is much less refined, having a slightly muddier sound, a slightly stronger but less articulate bass and also less detailed highs. With the ER4P, you can feel the clarinetist make a 'fff' sound when he blows into it. Also, the violinist's violin is has a woodier, warmer and more articulate sound. The highs of the ER4P are definitely shriller and more pronounced, but never fatiguing. Instrument imaging is actually quite good. The separation of instruments is clear cut and when all the instruments play at the same time, you're greeted by a warm rush of sound that makes you feel nice and warm. The ER4P is sooo detailed that you can even hear the clarinetist's clicks as he presses the metal "keys" on his clarinet! Now THAT is detail! The breathing of the players weren't apparent on the ER6i, but with the ER4P, you can begin to hear the breathing of the wind and brass players! This is an incredibly wonderful experience. Overall, at 30hrs, the ER4P has a much more matured, detailed and warm sound than the relatively boomy (througout all the frequencies) and muddy sound. Note the word "relatively" because the ER6i are in no way muddy!
I am now listening to Beethoven's 9th Symphony and the brashness of the French horns are realistically reproduced, so are the tremelos in the violins. Since the recording is a live one, the movements of the audience can also be heard more clearly than on the ER4P than on the ER6i.
One word: breathtaking.