No, they didn't copied Iron Maiden... The music, vocals and lyrics are way more interesting than any other heavy/progressive metal of that time.
Tates vocals sound operatic, dramatic and powerful.
The music is very melodic but also rocks and has excellent guitar work.
Thought-provocing social critical, philosophical lyrics about the mental struggle (fear, sorrow but also hope) of individuals in a confused and chaotic world. "I'm a fool in search of wisdom."