I have to ask, because well, they both are female doom duo's.
Not in the slightest. MoT are uptempo and caustic, Undersmile are slower and heavier (the guitar tone itself must weigh as much as the moon). Vocally it's primarily overlapping twin-female cleans, but of the very weird, off-kilter, psychedelic chanting type, much like Bloody Panda.
Argh, still can't get over how much I should love this, how much I want to love this, how much I actually love this when I put it on, and how I'm pummeled to the ground exhausted by the time I'm at track 4. Way too long for its own good, which is a pity. I love it but I find myself spontaneously listening to it very rarely since it's such an investment, both of my time and my energy.