Smaller bongs are more portable, but with bigger bongs the smoke has more time to cool before you inhale it, so your hits are smoother. I would say just don't go *too* small - if you want a really portable piece you'd be best getting a pipe rather than a bong. As for cleaning...I clean with my glass bong with surgical spirit and salt - pour it in, cover the holes and shake it up. Dunno if you'd use a different method to clean bongs made of different materials. I think some of the acrylic ones come apart for easy cleaning.