This fits into the "other" category of the polls, but I really like Yohimbine HCl. Not Yohimbine, but specifically the HCl powder form that Nutraplanet makes. ECA works, but Yohimbine is more potent for me. Also, ECA doesn't do much to supress my appetite whereas Yohimbine HCl completely shuts down my appetite for 3-4 hours as all the fatty acids are sent to the bloodstream. Yohimbine bark makes me noxious, but the powder in it's alkaline form is great. Tons of energy, and depending how much you take there are varying levels of how much thermogenesis and sweating one gets. Again, I really like it because it's dirt cheap and because is supresses my appetite as well, rather than just expending energy as heat.