How to search the image for an object with SIFT and OpenCV?

Question

i am working on a simple playing card detecting programme. For now i have a working Sift Algorithmus from here. And i have created some bounding boxes around the cards. Then i u

Answer 1

Is SIFT the best approach for something like this ?
As opposed to Haar classifiers or just simple template matching.

eg http://digital.liby.waikato.ac.nz/conferences/ivcnz07/papers/ivcnz07-paper51.pdf