If Magento is hosted on a shared server and 'PageCache powered by Varnish' is out of the question, would anyone recommend some of the other Magento page cache plugins like:

Booster: <http://www.magentocommerce.com/magento-connect/performance-booster.html>

Zoom: <http://www.magentocommerce.com/magento-connect/zoom-full-page-cache-1742.html>

Nitrogento: <http://www.nitrogento.com/>

Brim: <http://ecommerce.brimllc.com/full-page-cache-magento.html>

[update]

Lesti: <http://www.magentocommerce.com/magento-connect/lesti-fpc-4534.html>
(free)

Are they all 'just not worth it'?, is there one that stands out from a bad bunch?

Cheers,

Les