Here is a photo from earlier this year. From left to right, very shallow cup point, hollow point, and far right is a flat point. All three were cast of 20-1 alloy. All three were shot into water. The far left obviously didn't work, no different than a flat point. While the far right flat point looks impressive, it also impacted north of 1500 fps. Any slower and you would have to go to nearly pure lead to see good expansion. The middle is a true hollow point, nothing huge though. It was a 1/8" hole drilled .150" deep with a Forester hollow pointing kit.
I have better pictures, but the sight wont let me upload at the moment. I'll try later. I don't understand why people have the opinion that casting hollow points is voodoo. I'm just an average guy, and I've found it surprisingly easy to make hollow points work. They react about how you would expect, no black magic or sacrifices to the gods. They are also reliable. Fired into water, wood, dirt, paper, it doesn't seem to matter. Not every bullet is a mirror image, but I've yet to see one expand really well, and the next not at all. Stick to soft lead, 20-1 is the bees knees, although softer or harder can work. I've never seen good results with straight clip on wheel weights, but COWW mixed 50/50 with stick on seems to do well enough. It seems below 800 fps is iffy for expansion. The middle bullet in that picture left the gun at 1200 fps and hit about 20 yards. I also have one I shot into a log at 75 yards, with impressive expansion as well. I will upload pictures when possible.
As was stated, they are not that hard to cast. Pure lead is no fun, but a lead/tin alloy is the best casting bullet metal there is. The NOE mold pins take some getting used to. All I do is jingle them into place before closing the mold. The inset bar from Erik is a dream to cast with, no different than a plain mold.
If you are looking for a reason to cast hollow points, they make bigger holes. There is a lot of merit to the large meplat and heavy bullet approach, but some calibers lack the diameter, and all else equal, a good hollow point still makes a bigger hole. A whitetail deer is not thick, and penetration is grossly overrated. I always want two holes in a deer if possible, and hollow points are no handicap there. Some of it goes to personal preference. There was the question on here a little while ago about a full power hollow point 357 magnum verses a slow swc 44 special. Surprisingly about 90% of people answered 44. I'll take the 357 every time. My experience tells me a 180 grain hollow point 357 magnum can make a larger hole than a 240 grain 44 swc, and you get the benefit of less recoil in the process. I'm not sure if people honestly think the .280" meplat will make a larger hole than a bullet that expands over 1/2", or if they think a hollow point is incapable of passing through an animal? Maybe they think the hollow point is too destructive to meat? Either way is a hunting capable bullet, and people don't like to change their ways once they find what works.