I prefer mono-adhesive for photo-to-paper or paper-to-paper, and glue dots or KI gloo for heavy embellies.
I found a site that sells the mono refills super cheap if you can buy them in bulk, so I will go in within another person or two to buy some.
I know that a lot of people swear by the ATG, but I borrowed a friend's once and didn't like it at all. Too big and bulky, IMO. Everyone is different, though, and lots of people love it.