As Queen of Diamonds has already said, these two ships are basically identical. They are both in the Freedom-class of ship and only a few minor differences can be found between the three. For the most part, if you read reviews on one, it's pretty much the same for all. The only difference would be caused by the crew, which changes on a regular basis. So you could actually go on the same ship twice and get two entirely different experiences because the crew changed. Keep in mind that opinions are like bellybuttons - everyone has one! But what one person loves, another will hate - and people are more than apt to write something negative before they write something positive - just the nature of the beast.
We've been on 10 RCCL cruises (if my memory serves me right) and for the most part 8 of them have been pretty much the same experience with 2 of them resulting in a slightly less than expected experience (the ship was in need of refurbishment and it showed - plus the crew wasn't up to par).
So one person could write a great review one month and you could go on the same ship the next month and have a completely opposite experience.
As for a lack of review about the Independence, as was stated, up until this year, it's been Europe, so not a great deal of Americans have sailed on her. I think you'll see this change over the next 6 months.