Sure. Poor SMP support (but this has improved heavily over the years), ancient file system, no Bluetooth (not important if you don't need this), reduced performance (due to a lack of optimizations and security mitigations overhead), limited Wi-Fi support (this is for numerous reasons, but it's better than other BSDs)...
I could go on, but, for my needs, it works very well and some of its simplicities are a godsend.
Could you give some examples/samples of things you have ran into off the top of your head?