Neither of them are perfect. I've only done a little bit of comparison between the two (just the Reimu spellcard page tbh), and neither one has translations I like strictly over the other. Though it seems to me at first glance that the ones on the Touhou Wiki are more direct/machine translations.. Most of them seem to be more or less identical, but that's where I saw the differences come up. And little differences like Orb vs Jewel.
For example, Reimu's 珠符「明珠暗投」- TouhouWiki has it as Jewel Sign "Bright Orb Cast into Shade" vs HisoutensokuWiki's Jewel Sign "Enigmatically Casted Pearl". Not sure where the 'enigmatically' comes from here and TouhouWiki's seems like the more literal translation, but there could be a connotation to '明珠暗投' that I don't know, so I can't weigh in a definite verdict on accuracy.
Yeah, Touhou Wiki uses direct translations, so it's probably the more accurate one. One example is that in Touhou Hisoutensoku Wiki, one of Meiling's move is called Searing Red Fist, but Touhou Wiki calls it Radiant Rainbow Fist (I went and made some corrections to her page in Hisoutensoku Wiki after finding out about this). As Kanji contains Chinese characters (I'm Taiwanese), I can tell that it is supposed to be Radiant Rainbow Fist. I can understand why Hisoutensoku Wiki called is Searing Red Fist, since the the Chinese pronounciation for 'Rainbow' sounds the exactly the same as 'Red', but uses a different character. 'Searing' means burning and 'Radiant' means bright... Well, things that are burning are always bright, right?
About the 'Orb' and 'Jewel' thing... The Kanji character for 'Orb' can also mean 'Jade', which is a kind of jewelry.
I asked about this because I want my current Touhou fan fiction to use as accurate attack names as possible, though I sometimes leave out the '<insert something here> Sign' on purpose if I do not find that attack amazing, powerful, or destructive enough to deserve it. I'll probably be referring to Touhou Wiki for more accurate names.
Thanks for the answering my question anyway!
EDIT: Nah, on the second thought... I'll only put in the '<insert something here> Sign' if I feel like it for certain attacks since it makes the attack names sound too long.