They are both the same size.
The 432PD is aluminum and therefore lighter.
As you said, the 432 can shoot 32 H&R magnum as well as 32 long.
The 432 has an internal lock.
The 432 has a shrouded hammer, whereas the 30-1 hammer is exposed letting you shoot single action if you want.
The 30-1 is all steel, older, and 32 long only. It's heavier, but not by all that much. Probably about 19 oz.
I have a 431PD which is the exposed hammer version of the 432PD.
Plus I have a 31-1 -- the square butt version of the 30-1.
I think the 432 would be a better carry gun for self defense. The shrouded hammer, more powerful cartridge, and lighter weight are in it's favor.
I used to carry my 31-1, but switched to the 431PD right after I got it.
But the 31-1 is more fun at the range, and I can shoot it better. For range shooting I prefer the 32 long as it's cheaper, and seems more accurate in my hands.
Plus, I really like J frame square butts as they fit my hand better.
So, which to buy, depends on what you plan to do with it.
Every thread needs a few pictures:
431PD:
31-1