George and Edward both have good points but ultimately it's like Jim says, it's a subjective choice at the end of the day. There is some loss in efficiency using them vs. drawer storage. That said, one particularly thoughtful choice for the newer Systainers are the integrated rails for drawer slides, either custom or Festool brand. I used the relatively inexpensive versions (about ~40 bucks for 4 pairs) and they actually worked very well. I was surprised at how compact, durable and easy to install they were.

I'm also a fan of the Packout system by Milwaukee for larger boxes, drawers, bins and accessories, but those are very much as George points out, only meant if you have the space. They're more durable but a lot less efficient for space. In a pinch I used a Packout box to rest my friend's motorcycle on to fix a flat. Yea, they're tough LOL.