Good RSS Feed Parser to use on php file?

wp_rss is deprecated and you should use fetch_feed instead which gives you much more control and options over the RSS and what is fetched ex:

<?php 
// Get RSS Feed(s)
include_once(ABSPATH . WPINC . '/feed.php');

// Get a SimplePie feed object from the specified feed source.
$rss = fetch_feed('http://example.com/rss/feed/goes/here');
if (!is_wp_error( $rss ) ) : // Checks that the object is created correctly 
        // Figure out how many total items there are, but limit it to 5. 
        $maxitems = $rss->get_item_quantity(5); 

        // Build an array of all the items, starting with element 0 (first element).
        $rss_items = $rss->get_items(0, $maxitems); 
endif;
?>

<ul>
    <?php if ($maxitems == 0) echo '<li>No items.</li>';
    else
    // Loop through each feed item and display each item as a hyperlink.
    foreach ( $rss_items as $item ) { ?>
    <li>
        <a href="https://wordpress.stackexchange.com/questions/53424/<?php echo esc_url( $item->get_permalink() ); ?>"
        title="<?php echo "Posted '.$item->get_date('j F Y | g:i a'); ?>'>
        <?php echo esc_html( $item->get_title() ); ?></a> <small>By: </small>
        <?php echo esc_html($item->get_author()) ; ?> <br />
        <?php echo esc_html($item->get_description()) ; ?>
    </li>
    <?php } ?>
</ul>

you can read more at http://codex.wordpress.org/Function_Reference/fetch_feed