These are my favorites and the explanation to them...
I like..
The transformation ideas and how they fairies received them which most of them match to the reason for getting them. For example, Tynix has the key word "tiny" in there just switched the "I" and "Y" and then added "ix" to make the transformation. They go to the mini world and they become tiny. And mini and tiny are synonyms. So, I thought that was really cleaver. Along with, Butterflix, Charmix, Enchantix, believix...etc. All transformations. I love how they are put as and the history and meaning behind each transformation. I love the outfits too. They totally match each one.
Another thing I love are the location such as all the magic realms/dimensions. Like the oblivion place, mini world, and all of the locations that the winx ever had to go to. I just like how it was put and how they showed it.
Clearly, I just love it all. I mean the voices can be a little weird sometimes but what I mostly like are the transformations and the locations of the magic realms.
SO, those are my favorite things. I know I did a little logic work in my first paragraph but i was just breaking it down as my explanation. Haha.