I would also like to add my own Pros for each solution:
Pros of Matrice M200+XT: IP43 rating, collision avoidance, LiPo heating, ready for XT2 upgrade, ready for Zenmuse X4S, ease of preparation
Pros of DIY+FLIR DPR: 2in1 camera, redundancy(cuz its HEXA power), easy and cheap repair