Just thought I would share my experience since I own both bags. I originally bought the bagallini and found it made my back really sore by the end of the day. It also would not stay snug as the strap kept slipping which may have contributed to my back hurting. Mind you I never have back problems normally. The next time we went I bought the triangular travelon that snaps at the front and is worn on the front of a person like the bagallini. It is smaller which helps me not bring too much and weigh myself down like I did with the bagallini. I did not have problems with my back hurting at all with the travelon. My son now gets my bagallini for his few things like his autograph book etc. and does not mind carrying it. I carry my camera, ID's, a few misc items like lip balm, pen, moleskin, hair ties, a bandaid, Aleve etc. as well. I can put in a smaller bottle of water as well and have it stick out the top.
One hint I have is to scotchguard everything hats, bags etc. with scotchguard before going to Disney.
HTH,
Angela