The old saying "If it sounds too good to be true than it probably is" would most likely ring true in this case, you might be able to have problem free dealings with BlueHost and be very happy with them however in order to offer such good deals hosts need to oversell their servers in the hope that not many if any of their customers use all of what they are offered, that is what can often become problematic.
In other cases some hosts offer such good deals to lure you in but then deem your site to be too popular and force an upgrade on you.
I haven't had dealings with BlueHost before and some quick googling only turned up positive results even though they all sounded fabricated but at least there were no horror stories there. I wouldn't of course recommend switching from A Small Orange seeing how I'm a happy customer and a regular on their forums plus of course I like the whole Apple & Orange thing with the similarities between what they offer their customers.