Hi SIMS. I think that this question will be like nearly 95% of all other questions on this forum - you will get the answers that are pro "off-the-shelf" pre-manufactured food, and others that are pro self mixing your own food.
This is what I have noticed so far (I have been using PnP "Seafood Mix" and "Mussel meat" now for the past month and a bit). I have seen my fish go absolutely MAD for it, and have actually seen my coral polyps EAT when I put of this stuff in the tank, and target feed them. They seem to flourish with this home-made food mix. I forgot to add garlic, which I would have wanted to do as well - BUT I will do this with my next mix.
Using the "normal" mysis, artemia, daphnia, etc "blocks" from the LFS, I do not see the same responses from ANY of my life-stock. Yes, the fish still eat it, but my corals don't like it - not even if I crush it and reduce the size to fit the coral polyps sizes.....
So, until I can prove that this food-mix is somehow bad for my life-stock or aquarium (e.g. nutrient levels, etc), I will continue using it.
BTW: my nitrate levels have not gone up at all since I have started using this food mix...... And I feed the "juice" to my corals as well.....
Just my story - only time will tell if I should be doing something else....
I have reduced my feeding now to only in the evenings (taking it SLOWLY) from both mornings and evenings....