Collages and mixed media…what do you think?

What do you guys think of collages and mixed media art? Do you like them? Do they make good gifts? Would you buy them? Would you be more likely to get one if it was on canvas or wood panel and ready to hang or would you rather have it on thick paper and be able to frame it yourself? just curious…also thinking about making a collage for a friends birthday…she really likes owls…maybe some kind of owl collage. Please feel free to comment! I really want to know your opinions! 🙂