I have never seen that site before and I'm not sure if I will use it much but I will say this I like the results it posted for no cost websites. It shows my site as 1 - 12 of 48,500,000. I also like that I don't see any sponsored posting at the beginning.
I was just looking at Pagebull again and discovered that the bottom left corners of each result has a "?" and a "magnifying glass". The "?" shows information on the site of interest. The "magnifying glass" shows an enlarged image of the page shown.