With Sony's exit from the handheld market, Switch is going to be the only option left for dedicated gaming.
I'd like to note: While this is the current and recent future situation, that is not to say that Sony will stay out of the handheld business forever more. One of the principal weaknesses to Sony's handheld strategies from PSP to the Vita was the use of expensive, proprietary memory cards. If they designed a successor for Vita to be more accessible (internal storage and standard expandable storage, for example) and bundle it with a stream box connected to the TV, they could have a legitimate competitor to Switch.
Looking forward to getting my hands on Switch at launch!
The BuShA owns all!