I looove Kanashiki Heaven. I like it more than Aitai, which I'm really surprised by because I usually prefer C-ute's a-sides, especially if they're "cooler." I love Aitai as well, and Saikou Music's okay.
So I just saw the numbers it sold and holy cow when did C-ute get so popular? This bodes well for the future of H!P, those are Morning Musume first day numbers right there (excluding 123 of course).
^ yesterday I read that C-ute get so popular since Sekaiichi HAPPY na Onna no Ko the song sold not soooo much, but I heard many girls in Japan know the song and like it?! ...hmmm but I´m not sure