Interview questions: JK flip-flop vs D flip flop

[AdvaRes]

What are the advantages/drawback of JK flip-flop when compared to D flip flop ?
Why D flip flop is prefered for circuits implementation ?

 

[alaparthi]

Most of the times, we need a flip-flop for storage.
D flip flop is the simplest flop that is available. Just a storage flop.

Eg:
1. It is not efficient to use JK Flip flop for shift register operation. (This is what is required at majority of the places)
2. However, there are some counters that use the J-K Flip flops to reduce external hardware. Remembering the Q(t+1) = JQ'+K'Q, JK Flip flop can be used where this feature makes the circuit overhead simpler.

This is my understanding.

 

[shashir]

sorry but i didnt understand shift register????

could u plz clarify it more widely.also i want o know why D instead of JK in most of the case/
thanku
shashir