Variety certainly is the key to any angel's longterm success. Though, New Life Spectrum is the only exception to regular pellets/flakes. All my fish, get their share of NLS. It is definitely should not be relied on as the 'backbone' food.
NLS make a Marine blend. I use that and the Thera-A, both 1mm for most of my fish. My large angels get the large blend, and the puffer gets the 4mm jumbos.