I agree this is all very subjective, and we all approach travel photography with different goals and picture styles but having had a brief flirtation with m43 earlier this year I found it the worst of both worlds that was neither that light or compact (when you add a few lenses) nor as capable in terms of IQ as FF. Which lead me to where I am now: a FF system and large sensor compact. We all travel differently but for me its easy to choose: if i'm doing more photography than walking its the FF system - if its more walking than photography (when carrying camping equipment and food in addition) its the large sensor compact. I'm a believer that greater alertness and capacity for creative thinking from carrying a light system results in better photos during long days on ones feet in foreign countries - but that just my own conclusions to the compromises inherent in travel photography. Good luck with your travels.
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