I'm going to say that my personal preference has finally shifted to
aluminum.
I grew up on iron and still have them, almost all single-cavity moulds, a couple 2Cs, and they all did a great job. These were my dad's moulds and he turned them over to me several years ago, but in the interim, when I wasn't close to home, I ended up buying a few
aluminum moulds and learned to use them. They were cheap and cheap was a major in the criteria category at the time.
I ended up with a couple 6C
aluminum moulds just to get the bullets I wanted and got the hang of those, pretty much.
Once I discovered the custom mould makers, I ordered
aluminum, because I liked the volume of the 6C and the weight difference was pretty significant, besides I was used to using
aluminum by then. Now, I order 4C
aluminum moulds when I want something, because the 4C is a good weight with great production, and I never have to clean the blasted oil off them before using them. I put them away as-is and they are ready to go the next time.
I only ever had one iron mould rust on me, and it was a fluke. I've cast my 429421s from the same 1C iron mould for as long as I can remember, and it got used EVERY time I cast so I could keep up using that slow-poke 1C. I never had to oil it because it never got rusty in the defunct freezer I store them in, but it was a horrific sight when I pulled it out one day and saw RUST all over the insides. I got it cleaned up, but the
aluminum won't do that.
I can get interrupted in the middle of anything and I have to drop what I'm doing and take care of things. This is ithe main reason I don't shoot my muzzle-loader any more too. Maybe if I had leisure time I could plan, I'd still use iron, but the
aluminum 4Cs are easy to handle for an hour or two at a time and I do like that. They do cast just as nice a bullet as my old iron too.
A few of them say "LEE" on them, but I won't lie - I've had some stinkers. The ones I do have were the only choice for THAT bullet at the time I bought them. None of my moulds were made in China, if that means anything.
If I hadn't had a LEE mould to practice "de-gas-checking" on, I'd have never had the guts to do it to one of my custom-maker's moulds.