I would recommend LSD over MDMA; I find LSD to be easier on the heart, it also lasts longer, and is more euphoric than MDMA in my opinion.
Also, people typically don't gain a problem with either LSD nor MDMA, but some people do find MDMA hard not to want to use again on a regular basis like once a month or something like that. I did know a friend to feel an addictive propensity towards MDMA and they were into taking it multiple times a week.