I've been listening to Osaka Syunkasyuto (大阪☆春夏秋冬) quite a lot lately, in part because they actually do a lot of stuff with a classic rock sound (including some good covers), but also because I'm hooked on Maina's vocals.
This one starts out with about four minutes of very entertaining ultra-violence, then turns into a great retro-R&B ballad.
Such dramaaaaaaaaaaaaaa in the PV, but her voice and performance totally hook me in...
Edit: Oh, Youtube/Google ads...
If madness made us strong, we would all be invincible.