I've been thinking about this lately...Magneto believes in homo superior and harbors a lot of disdain for humans and Voldemort hates Muggles (also non-magical, non-mutant humans)...do you think their ideologies are similar enough that they'd get along?

No.

No. Magneto is an extremist (to a degree) while Voldermort has crossed the border to full fledge Psychopath.

Even if a white racist and a black racist might both hate Asians...it doesn't mean the two would get along. More than likely they would still hate each other for being different.

Voldemort would still hate any non-magical mutant, and while Magneto has mellowed on his mutant superiority a bit, its still there. Voldemorts goal of world domination would directly conflict with magneto's goal of mutant prosperity

All of this....plus Magneto just not being as pure evil as Voldermort would prevent them from getting past descriptions of their lives.

No. Voldemort sees humans as inferior. Magneto sees humans as an evil mutants must be saved from.