This album does not in fact contain the entirety of the LPs it specifies (although it says so nowhere): it's missing "The Rambler from Clare" from the first. The banjo medley "The Nine Points of Roguery/The Humours of Tulla" from the second is not listed, but appears after track 22, so the album actually has 25 tracks, not 24 (thanks to A. Watson for pointing this out).
That said, this album was certainly excellent value at its original price. Furthermore, the tracks from the first album appear here in stereo, although the LP was only released in mono.
The Johnstons are seldom mentioned these days except as the starting-points for Paul Brady and Mick (then known as Mike) Moloney, but for my money they were one of the best groups ever for Irish traditional music; and all the material here falls into that category*. They understand their material perfectly, they're first rate instrumentally, and their harmonies are stunning -- listen to "Fuigfidh Mise 'n Baile Seo", for example.
*OK, "Ye Jacobites" and Fhir a' Bhata are Scottish.