I used Site5 for the longest, maybe until 5 or 6 years ago. The problem with shared hosting is that many times they are unwilling to install software because they don't really know what it does or they don't want to support it. Basically they don't want to affect the rest of the server just by helping one person out. So installing that module might hurt another hosted site.
The reason I left them was because they had some crazy email filtering system. Basically they filtered it two or three times resulting in me not receiving emails. They would even block out emails from Facebook as well as other legitimate mail that I wanted to get.
Sure shared hosting is great, but you also have to settle for what they offer most of the time.
-Joseph
