Why are Mugen batteries sooo expensive?

[Sharrydan]

I find that the same capacity Mugen Power batteries are often nearly double the price of Seidio. Is there any difference in terms of benefits?

Like on Amazon, extended batteries for evo 4g: Seidio 3500 - $58; Mugen 3200 - $119 ?

 

[AngryHatter]

Maybe after the earthquake costs went up.