Currently there are variations of LSD that are becoming popular because of their legal stance. LSD is illegal but variations of it may not be - thus in some cases may be being passed off as LSD.
Even when there was lots of LSD around there was always the weird variations that just weren't very clean.
Often "family acid" was rated as the best. But the problem is every Tom, Dick, and Harry would swing their crappy acid as "family acid".
Most often you could determine good acid by the artwork on the print. Such as Alex Gray Jesus blotter, Alice and the Looking Glass, Flying Pyramids, etc.
So my point is - I just hope that what we're hearing as LSD is in fact good clean LSD.