Seems like a nice guy, but has clearly not been keeping up with the evolution of techniques in recent years as his knowledge is outdated at best and misinformed at worst. He has some nice trees but also a lot of really unremarkable ones.
I wanted to jump into this discussion as his website just launched it's first product and it's a 'grab-bag' lacebark Elm offering, which includes a pot and small shears. It's a blind sale of bonsai stock material (you don't get to see the actual tree you are buying) and the sample images suggest 0.5"-1" trunk with potentially good branch placement or nebari - but then again, it's a blind purchase so you'll never know. This isn't unusual or different from other retailers like Brussel's, Wigert's, or Eastern Leaf. However, the price is set at 295USD - this is about 3-4x the value of a small Elm pre-bonsai.
I see a lot of hate for the guy, but I don't see a clear incentive for him to overcharge or to put out bad information. He's a retired tech guy and likely has more money than he knows what to do with so a unscrupulous cash grab likely isn't his intention here. I'm curious to follow the development of this business and if Milton's products/content get better.