My intention is to know , what are the pros and cons of each registration type.
Do you face any issues with one method , such kind of issues will not be faced in other method. things like that?
scenarios like dynamic registration having advantages over static registartion and vice versa?
Some facilities (such as restart with the Data Guard Broker) will not work unless you defne an appropriate staticly registered service. Other facilities (such service failover) will not work unless you use a dynamically registered service.
Decide what you want to implement, and configure registration accordingly. There are no "pros and cons".
In addition to the other comments (especially John Watson's) please be aware that it is NOT an "either/or" situation. You can have static registration via the SID_LIST section of the listener.ora file, AND STILL have the instance dynamic registration. And nothing "special" is required.