I seem to recall that Hostgator gets mentioned in our forums, and I seem to recall that it is often positive. Personally, I don't recognize the ispaze name. I do not have experience with either of these two.
How big do you anticipate your moodle becoming? <100 students, > 2000 students? What is your knowledge level of computers and Linux (often recommended, but not an absolute requirement.)?
Most important, what is your budget, your time constraints, and staff constraints?