I would recommend taking both tours your first day in city. We enjoyed both tours although preferred the morning one- probably because it was a shorter distance but seemed to contain a lot more information and history. The afternoon seemed more focused on art throughout the city (we are just not huge appreciators of art, personal preference) - would be interesting if that was your cup of tea. Would have been much more interesting to us if we hadn't already walked circles around city on our own.
Daniel is a very knowledgeable, interesting guide. He is friendly and easy to understand. Can't beat the price!