Some parents have complained about the extra piece, the vent, and how it is a little bit of a hassle to clean. (babygearspecialist.com)
I can not think of any cons to buying this product with exception to the cap, I often pour too much syrup out of the bottle and closing it can be a little bit of a hassle when the syrup collects at the edges of the cap, but this can easily be prevented I just tend to be on the clumsy side at times. (amazon.com)
As popular as these were years ago, many parents think twice now as drilling a hole in the ceiling is a fair bit of hassle and obviously leaves a hole needing a patch up job when you no longer want the mobile. (bounty.com)