Pre market is good and worth taking part in, mostly when it is worth it at the end of the pre market period. Pre market gives a friendly price, which is cheaper than when the project gets listed in exchange and gives profits to those who participated in the early stage of it. Most times, this serves a room for the early birds to acquiring the coins at it's early stage for projects that gets successful at the end, yields good profit for all.
The only challenge faced with pre market is if the projects gets too much hype, it ends up with a dump by those who only participated on pre market to secure the profits obtainable at the moment, and when there is a dump, if the project is not well backed, it faces struggle. Most times, the coins gets locked up, so that the investors can get some profits, before any other who participated in Pre market can get out theirs.