Regarding Switch vs PS4 in terms of power, it's complicated.
In terms of raw horsepower, on paper, Switch sits closer to PS3/360 than PS4/XBO. However, horsepower alone doesn't tell the whole story, as the Switch has access to technology 10 years more modern than PS3/360, so it is massively more efficient.
It's like if you have a plane and a bus that have the same horsepower, but the bus can get stuck in traffic while the plane just flies straight to its destination.
This enables Switch to close the gap with PS4 enough that it can run the same games, just at lower settings. It also helps that the Switch has 3.2Gb of RAM available to games, which is closer to the 5GB or so of PS4/XBO than the less than 500MB PS3 and 360 have.
Of course, being a portable machine brings with it certain limitations as well; particularly memory bandwidth, which is the Switch's weakest link, so you have this halfway house of 7th gen horsepower and bandwidth with 8th gen GPU features and RAM capacity.
