I would consider it not safe because it was on of the companies mentioned on the NSA slides. 
You can still sync your Keepass(x) file with Dropbox if you have a good password (key file is recommended) on the database file.<p>Instead of Dropbox you can also use <a href="https:&#x2F;&#x2F;spideroak.com&#x2F;" rel="nofollow">https:&#x2F;&#x2F;spideroak.com&#x2F;</a>
They have a really handy program which let you control a lot of things and they are a &quot;zero knowledge&quot; cloud provider, all your data is encrypted.
Snowden recommends them: <a href="http:&#x2F;&#x2F;www.theguardian.com&#x2F;technology&#x2F;2014&#x2F;jul&#x2F;17&#x2F;edward-snowden-dropbox-privacy-spideroak" rel="nofollow">http:&#x2F;&#x2F;www.theguardian.com&#x2F;technology&#x2F;2014&#x2F;jul&#x2F;17&#x2F;edward-sno...</a>
For $12 dollar a month you get 1 TB, which you can use as a safe off-site backup location.