Australian-based site Capsule reviews Ratchet and Clank: All 4 One and gives a positive review of the soundtrack:
"The music of the game isn’t bad. It is quite good, actually. The music usually fits the action on screen and happens to bring some of the charm of the series. One particular track in the game that deserves a mention is the main theme. This track is often used in the various tracks throughout the game and it is a track worth listening to. It is quite catchy and somehow fits with the overall theme of the game, which is quite good."
Link to the review here.