For some jobs I have my stanley tote bag .Few festool boxes and I can use a large dewalt box to put in what i can use that day .Just saves so much carrying ! A multitool/ grinder. 18vSDS and 10.8v impact and drill . 2 batteries and a charger can all fit in one box rather than 5 boxes !I have the Milwaukee packout. If you're going into one job a day and need a lot of your power tools it's great.
If you're going job to job it's a bit of a faff. I will say it's as tough as old boots. I believe they have introduced drawer units for both the Dewalt and Milwaukee setups. There are other versions such as Trend but have only used the Milwaukee.