To be honest there are things I like and don't like about both. I like the overall style of the turnlock better but I tend not to close latches so I'd be more inclined to a zipper personally. But I don't like some of the details of the zippered bag, like how wide the straps are where they attach to the bag and the tiny keyhole (just seems out of proportion... I don't know).
By the way, is it just me or does "satchel" refer to a number of different styles of bags? I've seen manufacturers use it to describe bookbag type bags like the ps1, doctor bags like the Speedy and then totes like this.