I had to make this decision few days ago as well after I returned jaybird blue bird x, I had to pick between the 215, Dunn Titan 5 and the RHA m750i, I ended up going with the RHA and I'm glad I did they are freaking awesome and I got them for $100 on a sale, cos I heard a lot of people, as well as Linus, say that the replaceable cable on the 215 stops working, that might be a very small chance but still, so now to why I went with RHA, I did a lot of research on then turns out they have a lot of bass like the 215, have a over ear design as I use them for gym and they have never fallen out of ear , are made of stainless steel (which just gives them the premium look), have 3 year warranty. so yeah, you may have already bought the 215 so enjoy them, but this is just for other people out there in the same problem as you.
cheers and have a nice day