I noticed something while watching Sailor Stars (kaiteban) (<3 i think I understand why Miki love Pewter Fox so much, Chuu Berri baaaaa ( ) and... I don't know, It feels sometimes like the song we hear is straight from the CD. (I noticed mostly on service numbers).

I only saw some Anzamoons, Marinamoons and Miyukimoons, so maybe this wasn't always the case? And lyp-sinched or not, their voices are amazing anyway. It's not like they weren't the one singing.
It doesn't bothers me much as 90% of existing musicals have this issue, but I'd like to hear your opinion about it folks :B

So, are the songs lip-synched or not? What is your opinion about it?

This isn't really a debate, the SeraMyu series has been very open about it, some songs are lipsynched, most are not. The first two series (Dark Kingdom, Usagi Ai no Senshi) are almost entirely lipsynched (i believe Yuri Nishina and Keiko Hanayama are live), this was to ensure the success of SeraMyu. With SuperS Kaiteiban, they realised they had a hit on their hands and decided to be less cautious, some songs do remain lipsynched such as Solar Miracle Make Up in most of Anzamoon (this is because its a song that plays to give actresses time to change). Following that musical, most songs are live, however, you must take into account for some video recordings, their live version has been dubbed over with album version in some cases. Stars Kaiteiban's Chou Very Bad is live there is no doubt about this, no album version exists for that version, the lyrics are entirely different to the album, Stars Kaiteiban apparently had audio issues, you can hear it in the speaking as well as the singing. But most songs are actually live, some of them actually sound exactly the same live as they do on the album. Hope that answers the question. Earlier service numbers are often lip-synched, after two and a half hours of non-stop dancing, singing and acting, they do need a breath lol, have you ever talked to someone who works in musical theatre? Its exhausting work, they're shattered by the end of it XD

Thanks for all those infos Miki! ^^
And sorry if this isn't really quite a debate ^^" I just wanted to know people's opinion about it.

It's alright. I'm gonna lock it though cause I don't really feel like there's much to debate. Just ask Miki. Or put it in the myu section XD