I'll start by saying I bought this DLC at a hefty discount on Amazon (£3 ish in sale) and that had a fairly high impact on high rating.
If you were a fan of Black Flag (one of the best Assassins Creed games in my mind) then you will likely be happy with Freedom Cry, Adewale was a great, but underused character in the main game, so it's great to see him given his time to shine.
More of the same really, if you know assassins games then you'll know they don't vary hugely title to title, this was a short but fun side quest, well worthy of the price I paid, but WAY too short to pay anything close to what Ubisoft normally charge for it. Think I completed in under 5 hours with all treasures etc, hence marking at "only" 4 stars.
One day publishers well understand 4-5 hour DLCs aren't worth close to £20 at launch. Great service as always from Amazon.