We've installed Magento commerce platform on many shared hosting servers and they have all suffered. We've found the fastest, most reliable magento hosting is Simple Helix. They offer a $20 a month premium bandwidth and fast server speeds, which is great for anything but especially awesome for Magento's cart software. This compared to a $100+ a month dedicated server is a bargain especially for start up magento system and new ecommerce stores. Simple Helix also offers a magento one-click install which is great for our fellow developers! Go Simple Helix for your next magento commerce client.

Ping Statistics from San Diego
--- www.simplehelix.com ping statistics ---
34 packets transmitted, 34 packets received, 0% packet loss
round-trip min/avg/max/stddev = 70.182/73.322/83.744/2.919 ms

Ping Statistics from Atlanta
--- www.simplehelix.com ping statistics ---
60 packets transmitted, 60 received, 0% packet loss, time 59003ms
rtt min/avg/max/mdev = 32.001/34.268/40.002/2.122 ms