Personally I feel that Self study is a very good option for every student because without self study it is very difficult to clear any examination. The main reason behind this thinking is coaching also involves a remarkable amount of self study. One of the reasons to go for self study is the confidence factor involved in it. Successful self study may give you an incredible amount of confidence to deal with any kind of subject or course.
As per my opinion coaching is not necessary for CS final. But another truth is if you taking coaching then you can save lots of energy and time. If you are looking for one stop shop for CS final coaching, then it is a bit difficult here in Delhi NCR. No clue about other parts of the country. So it is advisable to go for self study especially in CS finals. But there are certain pre-conditions for self study:
1. Proper guidance is very much important.
2. Choose correct reference books well in advance.
3. Have regular discussions with your friends.
4. Self study may be a failure if you prepare without interaction with anybody else.
5. There are certain topics in CS and CA Final for which special preparation is required and self study may be harmful from the conceptual clarity point of view. So discuss these topics with your friends or with any experienced student.
6. Let me tell you a very important thing coaching also involves self study where as self study does not involve coaching. Reason being in coaching classes also concepts are discussed once or twice. But you have to understand those concepts by self study only.
Wish you all the Best