Well you seem to be a Nintendo fan so that complicates things. Breath of the Wild is phenomenal and I'm sure Metroid Prime 4 is going to be amazing. Arms is a fantastic fighting game despite not being traditional, but it's really only enjoyable with an internet connection as it's 90% online.
That being said when it comes to finical point of view definitely the PS4. For one PS4 games go down in price pretty fast, Switch titles won't be. Nintendo keeps their software prices high for as long as they sell. You will have more games on PS4, more selection, and a fantastic library of must play story based games.
If your a hardcore gamer who wants to play a lot of games then get the PS4. You'll be able to buy 2-3 older games for the price of one Switch title. The PS+ titles are getting better and often have interesting little nicks to try out here and there. Though if portability is a huge factor then the Switch is still a good option. Breath of the Wild easily has 150+ hours worth of content but you might find yourself struggling to buy more games over all.
