I follow his videos occasionally, he's pretty knowledgable with plants so I like watching and reading his content about plants. He's mentioned his liquid fertilizer but nobody talks about it so I've been hesitant myself... I have been looking into getting a bottle of some kind. Have been comparing Easy Green (Aquarium Coop), Vital (H20 Plants), and Growth Juice (Dustin's Fish Tanks).
My first and only experience was a negative one unfortunately. Ordered a bunch of anubias from him, probably $80 worth, and they infected my current anubias with rhizome rot. I have no way to prove this other than the fact that my anubias were thriving and perfectly healthy prior to adding the new arrivals in but I lost them all, old and new. I did email him to see if something could be done but never got a response. Lots of people have had good experiences so mine may have been an anomaly but it was devastating to lose plants that I had growing well for close to a year and I’ve not ordered from him since.
I have ordered a few times. Its usually positive, which is why I continue to order. Occasionally (due to nature being nature) plants will have issues like Lchi87 experienced, but in general his plants are great. I haven't ordered anything but plants from DFT though.