On Saturday, I was having an eargasm with my V4 Termiantors with one of my Epica albums, and some Nightwish, too.
The latest deep-cup VXD4 Darths will come off burn-in this week, but so far, they sound similar to the V4 Terminators.
If I was you, I would get a V4 Terminator, NOW, then a deep-cup Darth, after that, and keep both, or sell the one you like least, if you don't want to have 2 expensive cans at one time.
I like to switch between them, and other cans, too, of course. But, I ALWAYS will have 1 or 2 Darths around.
I had HD650, and SA5000, and D5000, K701, RS-1, SR325i, and *many* other FOTM, or other well-known cans -- the V4 Darths are better, to me, and are keepers. The others are gone.
I also will keep my HFI-780 and PRO 750, and also some other less-noteworthy cans, and rotate among them for variety.
Gotta have multiple cans.