Hi,
you have 3 different types of bikes there. While they are all touring bikes, the Carpe Diem is a lite touring bike, the 520 is a loaded touring bike, and the BLT strikes me as more of an expedition tourer. I have a Carpe, have ridden the 520, but not the BLT. So take my remarks about the BLT with a grain of salt. You can use the search engine to look at old posts that have discussed these bikes. I would first settle on the sort of bike you want. I'm gonna assume you meant tradtional touring....tents, stoves. The 520 is one of the cheapest good touring bikes. There are certainly cheaper ones out there, but I feel they make too many compromises.