I like how easy it was for me as an admin in setting up campaigns, creating segments etc., It's not too complicated but has enough options so there isn't much confusion when using this product! The ability of being able to create multiple versions within one campaign makes sense because sometimes people respond differently depending upon what they are doing or who else responds at different times during certain tasks (ie - emailing someone).
As mentioned above though we can have several variations within 1 Campaign which helps us track responses better than having separate ones would do alone. This also gives our clients more choice if they want something from only some version/variations vs all available choices across them all. We've been very happy thus far since implementing frogged into our business workflow process.