There are many different drawbacks of buying an iPhone. Firstly, the newer versions of the iPhone do not have a headphone jack. This means that you will have to use the lightning connection earphones that come with many models or buy the wireless ear pods separately for a significantly big price.
Apart from that, the iPhone universe does not allow users to add a lot of customizations. So in case you want to fully customize your phone without messing with the software, getting an iPhone is not recommended at all. Rather, you should go for an Android in case these things matter to you a lot.