Some pot metal razors are okay, and some are absolute junk.
Machined aluminum heads are better, depending on type of head, aggressiveness and one's personal preference.
Machined stainless steel heads are better still, also depending on type of head, aggressiveness and one's personal preference.
...and brass is absolutely fine and can hold it's own and cost a boat load less.
And if you made one of those stainless razors out of brass it would be heavier, and your tooling would last many times longer!