There is no real difference that I can tell between the two coin P/D Kennedy Uncirculated set for 2014. Just two coins in special packaging had a mintage limit of 200,000.
Now the 4 coin silver set is different. They are 90% silver coins with different finishes:
One reverse proof coin from the U.S. Mint at West Point
One proof coin from the U.S. Mint at Philadelphia
One enhanced uncirculated coin from the U.S. Mint at San Francisco
One uncirculated coin from the U.S. Mint at Denver
Mintage for this offering was 225.000.
All of the 2014 Kennedy Half Dollars all have the same portrait as the 1964 coins.
What I did not obtain was the gold 2014 Kennedy Half. This was 3/4 ounce of gold with a proof finish. Mintage limit on that one was 75,000 at a price of $1,127.50.
Remember that since 2002, the Kennedy Half dollars were not minted for general circulation.