i'm being playing Super Street Fighter IV:AE and I love Ibuki, I'm watching a tournament, and I don't see anybody play Ibuki, is it because Ibuki is bad? and if I want to continue with Ibuki, what is a good strategy for her?
Ibuki is very good in SSFIVAE and there are some Japanese players that use her (e.g. Sako, Momochi has also a quite decent Ibuki). See SSFIVAE 2012 Tiers for reference.
She is considered a rush down character with an awesome vortex. Basically you try to get a hard knockdown and then you go for ambiguous crossups with option selects.
If you can execute this perfectly then some characters, like Ryu cannot escape this without getting hit or having to block correctly. Crosscounter created a quite good free guide that explains everything.
Now here is why so few people choose Ibuki: