I know what lime tastes like.  I have never in my life tasted a cactus.  I thought they might be going for the beer/maragrita thing so maybe there is a taste of tequila in it.  Although tequila comes from the agave plant and that is not a cactus.  So maybe it is beer that tastes like lime and Saguaro cactus.  I would try it but I don’t know that I would like drinking a cactus.