Thanks for the reply.
Yeah, at times I listen to MS2e on just my Dragonfly, which is an amp/DAC combo and I hear a subtle difference versus LD 1+. Anyway you slice it, MS2e, while a lovely headphone for its price with outstanding detail and clarity, is smoother and more laid back than its Grado counterparts. I like a more forward and aggressive presentation but am also sensitive to brightness, so I have some conflicting interests to deal with.
I've considered DT990 but it has a reputation for very shrill highs on the order of SR325i or SR325is, so I've stayed away for that reason. Doesn't sound like you have that opinion though; your BH Crack probably tames them.
My goal at the moment is to "get my Grado right" but if I do decide to go exploring other brands, I'm actually interested in planars......in particular the LCD-2 intrigues me. It too has a very good reputation for rock/metal but is also very warm. I have a hard time wrapping my head around that, but I think it's the fast transient attack and very deep, extended bass that does it. Also looking at HE-400i a bit. Then of course I'd probably have to up my amp to Lyr2 or something like that and the wallet impact spirals out of control.....
I'm not overly confident in my DIY abilities but thanks for the tip!