Most posts to the Ecstasy Information Page Message Board regard specifics types of E. While this can be helpful, it is important to remember 2 details: location and timing.
The same "brand" of E can vary wildly from place to place. A dove in NY is probably not the same as a dove in CA. Anyone with a 2nd year knowledge of organic chemistry can perform the reactions necessary to synthesize MDMA. Getting your hands on the equipment and chemical precursors is not easy but not impossible. What this means is that not all E-pills are made in factory's somewhere or that they are all the same. They could be made overseas, in an abandoned building, a suburban home or down your street. Anyone with a pill press and a stamp can punch out copycats. If you get your hands on pills within 3 weeks of it hitting the streets then you are usually in good shape. After this point is when the copycats usually start coming out for the good pills.
Timing is critical. Chemists often wait for a pill to earn a reputation, then pump out copycat batches using crappy ingredients because crappy ingredients cost less. They are well aware that once a pill has earned a name for itself, they can ride the reputation generated by the higher quality batch. People often buy pills up based on their reputation, yet colors, stamps, and names don't mean a thing after enough time has passed.