Couple things to ask... What else were you running with it the couple times you tried it? What was the dose of Mast E as well as these other compounds (specifically test)?
For me, I can say I notice a difference between the two. Even at the same dose Mast E seems to give me a more full look. MastP I typically would use anywhere from 300 to 700mg/week, MastE 600 to 800mg/week. Also, I usually drop my AI when using Mast. Bloodwork confirms that my E2 stays perfectly where I want it (this doesn't apply to everyone).