My opinion -- and I am a demonstrator-- I HATE mono adhesive!!!
I find that it doesn't hold, especially for scrapbooking, or like the cards I keep out on display or swaps that I've had for over a month.
I LOVE glue dots. They are not messy, hold great, and are easy to use. You don't need many glue dots, usually just one in each corner of a cardfront or matte or whatever, as opposed to a whole strip on each side plus one down the middle of the Mono adhesive to get it to hold.
I only use Mono in an adhesive emergency, when I don't have anything else in my house!
The Dotto by Hermafix is good too, but is hard to refill until you get the hang of it.
For the money, go for Glue Dots!