Honestly... I didnt find yohimburn to be very affective... ECA stacks boast better results from my personal history with the 2 products... but this of course is only my opinion.. I think it has more of a placebo affect than anything else...
yohimburn should not be considered a replacement for EC but a synergist. for overall fat loss EC is better. for stubborn fat.. EC can actually make this worse through Alpha adrenceptor agonism (though more likely it just does not help there)..
NYC and EC have different properties.. and response varies.. they are both good.. ideally they should be rotated