These definitely fill a niche that the HE500 can't; the Didos are just a loaner, but if they weren't so much, I'd probably buy a pair for myself over the HE500 (
Yes, I've heard it) if for nothing but to get people that are curious about the hobby an idea of what can be done with a headphone and satisfy my growing bass wants. As good as the HE500 is, after hearing it again, with a better amp, it doesn't do anything
different compared to, say, my ZMF. Sure, it sounds slightly more organic, more coherent, more "there" than the cheaper ZMF, but a slight upgrade to an otherwise similar-sounding headphone is kind of silly in my situation in which I listen to a bunch of different genres and the HE500 wouldn't sound
fantastic with all of them, and I'm not getting rid of my ZMF (I painted/recabled it myself and nobody would want to pay even parts cost because it doesn't look that great). That part's what people questioned most about my previous setup, which was a bunch of warm-sounding headphones that I occasionally rotated. While the differences are obvious to me, they were only obvious because I knew to look for them, and it wasn't until a little rationalization that I decided that I'd rather have different-sounding headphones that don't always get used, but will be used if I'm in the mood for that particular sound signature instead of having just warm headphones that just flat out only got used because I felt guilty that I paid money for something that I didn't use all the time.
^^^That was kind of on topic.