OH YES IT IS!!!
I admit it wasn't a case of love at first listen with me, but when it hit me, it hit me like a bullet train. Yes, the atmosphere of the song is so perfect! And so perfectly crafted, it astounds me. And Mami's voice just oozes ALL THE FEELINGS, this song is so perfect for her and she brings out so much beauty in it! Ugh, it's just such a perfect song.
Ah, I love Tenjou wo Kakeru Monotachi too! I've always makes such good songs when all their singers combine their forces, and Tenjou was no exception.
I don't think we've seen the last of Mami, she's the biggest name I've has right now. She's also been making eroge songs at a steady pace, and she has a PSP game theme song lined up for release some time this year!