Both good in their own way, and have similar limitations re suspension and weight.
650 has almost double the power, so would be better if a lot of motorway work or high speed roads were being travelled.
Himalayan is a characterful bike; lazy power delivery, tractable and quite good fun. Will do easy trails with ease, but is wide and low so clearance is limited in ruts and over sleeper size bumps/steps. They do make it though.
Suggest you need to get out and try both before you commit.