I use HostGator, NameCheap, and SharkSpace shared hosting at the moment.
HostGator does have helpful support, but their hosting isn't always fast. During peak hours in the US, the server my site is on frequently reaches 40.0 load and higher (it's a 16 CPU server), causing MySQL outages, slow loading, and so on. Maybe I just got unlucky by being placed on this particular server, but I'm not too impressed.
NameCheap seems good - there were a few outages months ago, but overall it's solid. Surprisingly enough (since it's not a very popular host), SharkSpace is probably the best shared hosting out of all I've tried. No outages as far as I noticed, always fast loading.