I did a test with BoxCryptor last year and was not too pleased. For enterprise use with the necessary master key, it's expensive too, and you still have the disadvantages of Dropbox. On the other hand, if you are a Dropbox user and willing to pay for BoxCryptor, the solution works flawlessly.
Also, keep in mind that Boxcryptor and Boxcryptor Classic are two different products. If sharing files in an encrypted way with other people or having a master key is part of your use case, Boxcryptor Classic is not a great choice. But if you just need a way to store your own files in the cloud, with seamless sync between machines, and without privacy concerns, Boxcryptor Classic has worked very well for me.
