Is a modular stackable tool box better than a traditional rolling tool chest?

It depends on use. Across specialist subreddit discussions on r/Tools and r/MilwaukeeTool, modular systems (Packout, TradeStack, Keter Stack-n-Roll) are favored when tools travel between jobsites, while traditional multi-drawer rolling cabinets win when the chest stays put in a garage and storage volume matters more than portability. Modular systems generally cost more per cubic inch of storage.