The range on the stock controller is good enough. Unless you're flying in a highly populated area or going for a record distance then i dont think it is necessary
Although, I have definitly noticed a clearer image feed, less cut outs (black and green screens), increased range but haven't pushed it to its max limit
The atlas weighs just under 600grams without the mounts. so imagine 600 grams hanging off the end of your controller - plus im using an ipad so it gets pretty heavy.
I mainly just fly with the whips, and use the panel when i fly in a highly populated area or in the bush as an extra precaution.