it really comes down to what exclusives you want to play. god of war, mlb the show, spiderman are on ps4. halo, forza, sea of thieves are on xbox one.
you need to pay to play online for both, and its $60 / year. though microsoft has Bing Rewards from their browser Edge to earn points just from searching alone. and you can earn 12 months of Gold in around three months real time if done properly.
i have an xbox one x since ive always had xbox. i have nothing against ps4, and would like to own one, but i felt it was never justifiable for the exclusives alone. i'd play maybe spiderman and mlb the show, but xbox would still be my primary console.
look at getting used systems from stores like best buy and game stop. i know for games, you have a week to return to get a full refund back. so see if it's the same for consoles or different for used consoles. it may not be convenient, but it's an option to try both, and return the other for whatever reason, and get your money back.
if you dont have a 4K TV or don't care about super high graphics, then the PS4 and Xbox One S will be sufficient for the casual gamer. Xbox released a digital only Xbox One S, so make sure you get the unit you want if you still use discs.
this summer Sony and Microsoft are expected to unveil their next gen consoles. Xbox will be at E3 next month, and Sony won't. they're doing their own thing. so if you can wait a little longer, see what they announce, when and how much. then decide if you want to wait for those systems, or go ahead and get one now. maybe get one now, the S or PS4, then get the other's next gen system when it releases, rumored to be next year.