It's SLOWwwwww. Unless you get some decent VDS hosting or a dedicated server. I think Vidahost have a Magento hosting plan with SSD servers and whatever which should be fine but I wouldn't be running it on a common hosting package it's just too slow.
It's so inefficient and bulky that you would need a development team on it. The admin panel is also very complicated. User experience is getting big so it's good to have fast loading sites, and also an admin panel that makes things easy rather than having 1000 menu and sub menu options.
Am sure a lot of people love Magneto but for a lot of my clients they want quick loading sites that are easy to maintain, sorry Magento.