I have always toured with panniers, but have frequently toured with others using trailers/bobs.
It really is a matter of personal choice.
As a pannier guy, I am jealous of a few aspects of trailers/bobs.
How light the bike is and how you can disconnect in a jiffy.
How easy it is to pack, unpack, and find things.
Drawbacks of trailers/bobs seem to be -
Very hard to park the dang combo - esp. in town.
More expensive or impossible to use some forms of transportation.
(Limitations also apply to trikes & recumbents)
As for weight - when you combine the weight of racks & panniers,
I think it all evens out.