Rocking Sleeper Dangerous???

So I have been a fan of the rocking sleeper since my niece had one for her baby but after reading reviews I'm not sure I want one. Iwanted one to use in place of a bassinet like my niece did. She got me it for my baby shower but now I'm considering taking it back and getting a regular bassinet. I seen a post on here with comments saying they aren't safe to use that way and  The reviews for using it as a sleeper are scary! Is anyone else thinking of using this for a bassinet? What are your thoughts???