How to check for specific meta box value on front end and output accordingly

Is this what you need?

$size = get_post_meta( $post->ID,'meta_box_musicreleases_featrelease',true );

if ($size == "display_lrg_release") {

    //do your large thing here

} elseif ($size == "display_sm_release") {

    //do your small thing here

} else {

    //do something when no radio is checked

}

…I think so.