Please be aware that at the moment there are some issues involving Dropbox and Lion, in terms of compatibility. They are currently providing a “forum build” (beta, I think) that addresses the problems, and it can be found here (but I must stress I have not tested it myself).
If your workflow depends upon synchronisation between Scrivener and Dropbox (most commonly to a mobile iOS or Android device), you may have difficulties getting this to work right now. Fortunately both Lion and Dropbox are just slightly popular, so I’m sure the Dropbox team are burning their knuckles off to get things compliant and this should be a fairly temporary condition.
In the meantime, for mobile purposes, you can use Simplenote if your device supports it, as a standby for your preferred text editor. Or be brave and try the beta. 