The first album is a worthy-enough follow-up to The Spoonful - perhaps not as essential as their four main albums, but very nice.
The Four Of Us has a few surprisingly great hard rockers, but the rest makes one wonder why he bothered. Some old hippies will disagree.
Third album
Tarzana Kid is a sleeper - I quite like it. A nice chill-out album.
Welcome Back is a dog, thrown together under pressure after the unexpected 45 success of the title track (which I do love).
There's also
this package which, though more expensive, includes all of the above plus
Cheapo Cheapo Productions Presents Real Live John Sebastian, which is many fans' favorite JS album. (An earlier Rhino Handmade set with the same cover included additional live recordings, not included here.)