Hi,
The ultimate pdf annotation software I recommend is MAXQDA. No exaggeration, it can beat all kinds of pdf readers. Although the software is mainly used to do qualitative data analysis (QDA), the logic behind QDA (coding system) is very suitable for bibliography annotation and management. With it, you no longer need to search for that very sentence you read several months ago in a mountain of references, no need to transfer your highlights. The software is commercial and not cheap, but I never regret to buy it. One hundred percent recommended!