Hey Aaron,
I switched because I wanted to be more environmentally responsible.
I chose to go with humic acid because it makes the nutrients in the soil more available to palms/plants to take up. It also adds a lot of organics.
I have a friend that goes fishing quite a lot. He would bring home trucks full of fish when he went on his weekly fishing trips with his buddies to Mexico. He is also into palms. He told me in preparation for his garden, he dug up his soil four to six feet deep and buried six ft tunas into the soil. Anyway, his yard looks great.
Fish as a fertilizer was something I always believed in, but since I don't fish, I looked for a fish fertilizer. I have heard of bad experiences where the stuff was not stable and burned my friend's plants. Most of the stuff out there is cooked, which makes it smelly and unstable. When I was doing research, I found out that if the fish was cold processed, it would be much more stable and wouldn't stink as bad. I liked what I heard so I have been using it since.
Seaweed is supposed to help build the cellular walls of the palms/plants so that they can handle more adverse conditions. Anybody that buys from Jeff Marcus will here him preach about the benefits of seaweed.
I can't say that the palms are doing any better, but more importantly, I do not see them doing any worst. I will say that I have A LOT more worms, big worms, now than ever before, and greatly improved soil drainage.