I voted for Ben just because he has these so-called stories of his time with the TMNT
And I didn't really like Zach, but it wasn't because he was a "fifth turtle" it was mostly because when I was younger I thought he got in the TMNT's way. But I suppose if I where to see the episodes that have him in them again I may have a different oppinion now that I'm older.
You never, I could find him tolerable now. My oppinion (slightly) with the red sky seasons for the better.