Right now, I would argue that the Legend of Zelda: Breath of the Wild is the best game on the Switch at the moment. This is a biased opinion because I have not played Mario Kart Deluxe yet and hoping to buy Splatoon 2 this weekend. I participated in the Splatfest and this past Saturday's demo and feel this game will be in the top five of the best Switch games for 2017. Also looking forward to Mario Odyssey.
Nintendo's marketing for the Switch has been going very well. Much better than the marketing for the Wii U. I've been playing since the Switch was released in March. My PS4 has been feeling rather lonely.