My best advice that I discovered works like this.
start with what you can get near to you. If it has to be shipped than that's a bummer but you can work with it. It best to get local or semi local so if something happens you can go grab what you need and not have to grab something you haven't used before because you needed it now not then.
After that, Avoid the ones with way too many supplements. My basic premise is simple, if you need that many ingredients to have a successful grow that blows your mind then it is best to assume they have a line that is not complete, contains PGR's, or is nothing but a lot of expensive gimmicks or overpriced black strap molasses. Lines like Heavy 16, House and Garden, Canna, all how reputations and very few Supplements. In fact their base alone will give you good results and some how some of the few things extra really do what they claim although there tends to be at least one, or more, that does nothing at all. beware of "Humbolts Own" brand, they have PGR's (Plant Growth Regulators) many have been banned for any usein anything other than ornamental due to how they build up in plant tissue. Some PGR's come from nature like what may be found in alfalfa. Humbolts Own has gained a bad rep, they could of changed there ingredients but they still make the products that can stop seed production if you have a herm. If it is too good to be true than it is Probably loaded with PGR's.
Price is another to consider. I have found that cheaper brands tend to be... for lack of a better definition, "dirty". For example, and I am not knocking the brand, but General Hydro tends to cause a build up of solids with a small amount of use. Koolbloom is a good example, you will see little brown bundles start to build in the rez with one use. Some say it is because of poor sourcing of material and I will agree it seems to be the case but the price point compared to say Canna is night and Day. Or House and Garden which is easy for me to get and has proven to be a very expensive and clean line. I have fee samples of General Hydro that was given to me from hydro stores over time I just cant seem to bring my self to actually pull myself away from house and Garden and give it a whirl. Been wanting to and started once only to continue with H&G anyways.
Big suggestion and I hope you follow this one. Pick a line and stick with it and don't mix till you get familiar with and good at reading your plants. If anything just use the Base with maybe a light PK booster if the line you pick does not carry a flowering variant.
I'm a hydro guy myself and have a love of COCO and feel it is a very forgiving form of hydro that has its own quirks that I have grown to love. With soil I always grew true organic and did not use Concentrates which is organic based not true Organic in the sense of synergy between plant and soil. I found through Hydro that I can do better than mother nature LOL. Than again, mother nature Likes and Fights for balance and the goal is to offset that balance in hopes to produce more. thus, take mother nature out of it and feed direct with a mostly inert medium. I say mostly because COCO is a beast all its own and requires a little knowledge that apply to it alone.
Hope this is helpful, there is a really cool way to grow true organic that was developed by a breeder called subcool, its called supersoil and all you do is water once you make it and it feeds to completion. It works good, gives great results and is so easy. Good luck happy growing.