BlueHost doesn't rate all that badly on the shared hosting chart (I am tracking this data - they are 6 out of 19 among some of largest providers). That sort of behavior sounds like crap, but it happens to most of them because of the nature of shared hosting. I am not sure that half a day to get a SQL load under control is normal though. I've had hosts just suspend my account right away when I go over or they kill the offending script.