ive been practicing Kundalini for about a year and half now coupled with my Hatha practice as well. it does share and differ in contrast with traditional Hatha yoga with more pranayama focus in my experiences, even through pranayam is central to hatha as well. kundalini for me, is powerful if you make it. im not too familiar with the all the mantras (im no sikh) and what not and not too familiar with yogi bhajan, however i have seen some youtube satsangs of him and was unaware of the criticism depicted towards him. that said, its an amazing practice to incorporate. check out this kriya, it is pretty intense..
sodarshan chakra kriya
http://www.mrsikhnet.com/2008/10/16/sodarshan-chakra-kriya-meditation/
let me know what you think