I have undertaken SAP training (HR) from SIEMENS, Mumbai. In my opinion you should go for inhouse training module. Don't see the cost. It's really helpfull because the trainer will guide you in all the way till training ends. Trainer will also suggest how to go for e-learning and approach for certification exam.
Both the institutes (SIEMENS & Genovat) are good. Go ahead...
My best wishes..
29th December 2009 From India, Ahmadabad