Unit 4 + 2 were 2 years behind contemporary bands during most of their career, at least soundwise. Their first records in 1964 sounded like they were made pre-Beatles, instead more like the Critters or maybe the Honeycombs. In 1966 they caught up with the typical vocal-harmonized merseybeat done by the Beatles or the Hollies around 1964. And long after "Pet sounds" and "Revolver" they became a bit more experimental. But what's the rush?
I don't care too much for the first 12 tracks or so here (except for the hit "Concrete and clay"). Pre-merseybeat-but-softer-than-rock'n'roll isn't really my thing. But the rest of it is really good. This is a good example of a mediocre group evolving into a really fine band.