MDA is basically the psychedelic predecessor to MDMA. It's less "loved-up" and more "trippy", however, you may still find subjective similarities between them. MDxx is just a term used to refer to either MDMA, MDEA, or MDA in a report. All that it means is that the reviewer does not suspect many adulterants in the pill, yet they are not sure if the pill contains MDMA, MDEA, or MDA. Please correct me if I'm wrong