A few articles ago I explained the distinction between 'real' and 'street-legal' insurance. Basically, one type, you buy, because you really want the financial protection; the other type, you buy just so that you won't get a ticket if the cops stop you.
I think Magnum Insurance sort of falls more in the middle. They don't seem as dodgy and unreliable as the other low cost insurers, but they're pretty cheap nonetheless. They have a large Hispanic clientele, so if you prefer to speak Spanish you'll be able to do business in Espanol with them.
A friend was insured by them for 2 years. Now, she never had a claim, so we never got to see how their customer service was like, but she has pretty low tolerance for dodginess, so the fact that she remained with them is a good thing, I suppose.
I would recommend Magnum if you are looking to get insurance that may be more reliable but still won't cost you more than your car's worth. (note: you should only be the market for cheap insurance if, in fact, 'regular' insurance premiums would cost more than your car is worth)