Yes there are side effects, there are fucking side effects to almost anything medical.
The side effects are minimal at worst considering you have to go into the doctor every 3 months for testing (both for the side effects and a full STD panel). If they notice an issue they take you off of it.
Condoms are not 100% though, neither is prep. Its just another option and if the US was not being gouged in the price of prep, the cost would not be much different than the cost of condoms depending on how frequently you are having sex.
I am showing personal responsibility by both myself and my husband using Prep and getting tested regularly.