BI Unclear What Certification and Why ?!

Yeah Gurus,

i work for a company in germany and am into BW.,.thought would be useful to take a certification in BI...

question:

Which certification is the best as of now..(2008) ?

if ur gonna post links with this 4s and 7.0 certification please tell me what is the difference and which is the best.

Thanks in advance

-Alf