Ecstasy is just like any street drug. While the drug itself hasn't been found in any studys yet to cause long term problems. It is produced and distributed in conditions that match street drugs. It can and is very often cut with things that are VERY DANGEROUS! If you are gonna do it, test it. There is a reason why there are e testing kits. For info on the drug and testing see:
http://www.dancesafe.org
Also ABC did a show on it a couple weeks ago called "Ecstasy Rising" it's an hour long and gives a fairly good impartial view of the drug, it's history and where it sits in todays culture. If you want a copy of it icq me and I'll send it to you.