The debate about when to add fruit to a melomel isn't really a new subject and I know there are tons of threads on it already. There is a the add it in primary camp and there is the add it into the secondary camp, and a few inbetweeners....
That being said...
This is a great podcast about an experiment that was done, two identical batches in every way except one had the fruit in primary and one in the secondary and the results of having it sampled by a variety of people from those new to mead to certified judges. The results are interesting.
I don't believe it really states that one is better than the other so much as it makes it very clear how the results of each method differs greatly and is quite detailed in explaining the difference between them. It would be especially beneficial to new mead makes contemplating their first melomel.
Scroll about a quarter of the way down the page and look for....
June 28, 2012 - Fruit Mead Experiment
Home brewer Tim Leber shares his experiment comparing fruit added to a mead in the primary and in the secondary.
- Tim Leber's data sheet (PDF)
iTunes | Streaming mp3