SoundMagic E30 or PL11

Hi

I realise that there's a price difference, but could anyone let me know who's tried both of these what differences they found between the PL11 and the E30? Is it worth the extra money for the E30?

They'll be used to listen mainly to MP3 for Rock music on portable players....

Do either of them provide sufficient sound insulation to act as ear protection and / or in ear monitoring for rock band practice and performance? (a tall order, I know...)

Thanks