I just returned from a month long trip with my new Synapse 25. I have decided that this is the perfect travel backpack. I have a S19 and love it but it is just a little too small for an extended trip. I can cram everything in but then it is really hard to work out of it.
On the other hand the S25 is Goldilocks (not too big, not too small - but just right)! I travel super light and have given a lot of thought to what I carry and the 25 works like a charm - everything fits with a little room to spare. Of course, the 25 has all the same stellar design features of the S19, it's just a little bigger. When I carried it fully packed, it looked like a normal daypack. How do they do it?? Somehow TB has reversed the laws of physics!!
I am planning a 3 month trip around the world, with only my S25, beginning in November and will post my complete packing list soon.
Final word - the Synapse 25 is the BOMB!