I have both aluminum and open pour silicone molds.
To me, aluminum molds are the easiest to use, because I have an injector.
I am just a hobby pourer, and make baits for myself and a couple of buddies, so I love the Essentials Do-It molds because they are cheap and they work.
I have several ES Do--It aluminum molds, like the 3" grub mold, and I can just heat up a batch of plastic and shoot enough grubs for a few trips. Same with their 5" ES senko mold, and their Ripper swimbait mold. Because they were inexpensive, I have two of each, so I can pour enough from one batch of plastic for a few trips.
But I still use my open pour silicone molds a lot, because I can easily make a laminated swimbait with them, and, because they are so cheap, I have five 2 cavity molds for the Lurecraft skinny dipper copy. That lets me pour ten baits at a time, and, because I can pour one half of each mold with the same batch of heated plastic, I am more efficient. I don't have to reheat my plastic during my five mold run, and that makes my plastic colors stay true longer, since reheating eventually changes plastic colors for me, even though I add heat stabilizer.
Having cheap molds has encouraged me to play around with different colors and mixes, and made bait making more fun for me.