Hi Guys, totally new here but i wanted to chime in. I have both the 215 and the 750 and I always turn to the RHA whenever I just want to have fun listening to my music. They are not totally neutral, but they are much more even than the 215. I mind the 215 to be a bit too muddy. I think the main thing g going. For the 215's is that for just under 100 you get removable cables. As for burn in, I can say that the 750's improved with burn in. Whether its physcological or real, I noticed a difference with about a full 24 he's. From there they just kept getting better. I will definitely be getting the T10 (without mic) when they release it next month.