Dropbox seems to have two major value propositions: ease of use, and multiplatform. If you just use it on desktops, there are already several far superior options. "Ease of use" isn't sticky.
The big challenge is mobile. Dropbox's main stickiness is when developers adopt the Dropbox API, particularly on mobile. If you just use Apple for mobile, iCloud is in some ways superior (although has Dropbox's same horrible security). There's no one doing a better job than Dropbox of crossplatform on lame devices like iOS and Android in addition to desktops (and game systems, etc.).
(I admit I'm pretty biased against Dropbox because they both lied blatantly and horribly about security for a long time, and then, when caught, did a minimal job of just handwaving and continuing as before. They make file security markedly worse for users than it was before Dropbox.)
I don't think "dropbox for teams" is much stickiness; I don't know of anyone using it in serious deployments, and in a serious deployment, switching wouldn't be that hard, either.
"(I admit I'm pretty biased against Dropbox because they both lied blatantly and horribly about security for a long time, and then, when caught, did a minimal job of just handwaving and continuing as before. They make file security markedly worse for users than it was before Dropbox.)"
Don't forget they were implicated as "coming soon" in the whole PRISM/NSA saga. No thanks.
I agree on pretty much all points - and wanted to add why I think Dropbox for teams is a horrible, horrible thing - well sharing anything on dropbox is actually bad.
First, one typically has a private dropbox that they keep a bunch of stuff in. When one joins a company that is using dropbox for teams - it cuts off access to your personal dropbox, and whenever the company has rule over your account - if you leave the company, lets say abruptly, you can lose access to your data.
I don't care what anyone says about any employment relationship - there is some data that is private and crucial, and you should never save any of it in a shared team dropbox.
Finally, sharing things with people via dropbox is a stupid and inefficient way of handling sharing; Assume you have a paid 50-100GB Dropbox. Storing large files/data in there is no-issue. Sometimes you'll want to share out a project directory with another user - but they may not be a paid dropbox user. If they join your shared folder, that data gets replicated to them and they get that data deducted from their available space. So, dropbox is "counting" the space for that data on both accounts. If that other user has a small or mostly full account - that project share could bring them to their cap.
This happened to people I shared data with on large projects many many times.
If I share out a folder from me to you - and you join my share - you should get a free connection to that share, as it is using data from my account limit, not yours.
The big challenge is mobile. Dropbox's main stickiness is when developers adopt the Dropbox API, particularly on mobile. If you just use Apple for mobile, iCloud is in some ways superior (although has Dropbox's same horrible security). There's no one doing a better job than Dropbox of crossplatform on lame devices like iOS and Android in addition to desktops (and game systems, etc.).
(I admit I'm pretty biased against Dropbox because they both lied blatantly and horribly about security for a long time, and then, when caught, did a minimal job of just handwaving and continuing as before. They make file security markedly worse for users than it was before Dropbox.)
I don't think "dropbox for teams" is much stickiness; I don't know of anyone using it in serious deployments, and in a serious deployment, switching wouldn't be that hard, either.