New CN rom user will be quite frustrating when they first use it. They will find lots of issue compare to other phone. But once u have done with all settings, u wont see ads or big issue. CN rom phone is not a phone which u can use it out of the box. U need to do quite alot of setting. Sometimes despite u alr done with whatsapp setting, the msg will still lag from time to time. So u need to do another thing to solve it (not the usual setting in the phone).
Some app/feature cannot work as well. Like whatsapp call. It will not auto pop out. U have to manually open whatsapp to see it. The good thing is the price. Flagship phone can be few hundreds cheaper than global one.
CN rom user are mostly laojiao old bird. Alr very used to it. So all those issue ppl are complaining, its a small issue to us. It just like drinking water or breathing.