Agreed, a single card is the best option, however, to say Nvidia is dropping SLI support doesn't match my experience, I'm finding it works far better than my previous SLI setups and support in newly released games seems strong.
It's still imo a good solution if you want a big performance boost.
As long as you don't want to play BF1

having 4 'seperate windows' showing 4 charts/or video or general browsing but effectively giving me a 4 screen setup on the one 40" 4k tv... the resolution allowing me to have genuinely usable sized windows without having to click about and swap browsers etc. mainly for trading but ability to leave one for general browsing etc... gaming would ideally be fullscreen and 4k or otherwise,