i prefer "splendid world" because it moves away from the typical power metal sound most of these touhou bands take. Instead they go the opposite direction with doom metal and stoner rock, two genres that should not mix at all with the fast and high energy nature of touhou. Its not my favorite album of them though, that is 朧夢紅月 ～Vaguely Dreams of Scarlet Fullmoon～
They new album "If" from C75 has some great stuff on it, starting with a nice "The Gensokyo the Gods Loved" and then followed by a great remix of "Maiden's Capriccio". "Invisible Full Moond" and "Mooned Insect" are also good.