The packaging of the album reflects the contents quite well, in that one sticker calls him 'the voice and guitar of Pink Floyd' and the other highlights the inclusion of 'all the songs from the {solo) album On An Island', and two ost-Waters Pink Floyd songs (High Hopes and A Great Day for Freedom).
The Pink Floyd songs are well-chosen, including the first four tracks of Dark Side of the Moon and Shine On You Crazy Diamond. These are presented in almost precise replications of the record versions (assisted no doubt by the presence in the band of Richard Wright (keyboards) and Dick Parry (saxophone); in a way, this process is so accurate as to become pointless - why not listen to the original version? Echoes is stretched further by a long and meandering, almost jazz-style, keyboard / guitar work-out. 'Fat Old Sun' is rescued from the obscurity of Atom Heart Mother, and is better than the original mainly from improved vocals.
The solo material is worse, and it's hard to work out why. Partly, there is the obvious point that to choose ten Floyd songs from 15 or so albums is easier than all of the songs from one, so you would expect some drop in quality. But beyond that, the solo stuff suffers because the arrangements are guitar-heavy and lack the sophisticated interplay of a band where all the instrumentalists contribute. Finally, it must be said that Floyd's musical style, and Gilmour's guitar and voice, is prone to grandness and bombasticism, making them better suited to subjects like madness, war and death than seaside walks and being in love (this isn't quite true: the albums from 1968 to 1972 included a batch of touching whimsical murmured emotionally sincere tracks, but these have been largely overshadowed by the 'classic' (Waters-written) more popular work). As a result, the On An Island sequence comes across as strained and aimless, with nice (mainly instrumental) moments but no momentum.
So the album isn't bad, but hardly makes a case for being a necessary purchase for Floyd fans.