Some time ago, Microsoft has announced that the OneDrive for Business client which is included in Office 2013/2016 will be unified with the OneDrive consumer client which is included with Windows.
After a long wait, announcement has been made that the public preview was here – see http://blog.hametbenoit.info/2015/10/01/office-365-sharepoint-office-onedrive-for-business-client-is-being-updated-finally/
So, I have received the notification to get the new client. I will no go through the installation steps are this is really simple: you need to download and install a new client and set few registry settings (if you got the notification, you have all the details – PS the link to download the updated client is in a Word document)
So, I have installed this preview and so far it starting to reconcile me with the OneDrive for Business client 
So, once you have installed the new client, you will have 2 options: adding your OneDrive for consumer account (if not yet already done with the “original” client) and your OneDrive for Business account
When adding a business account, you will be automatically set to synchronize your OneDrive for Business space (no, no option to synchronize SharePoint library now, maybe in a future release) and you will be able to select which folder(s) you want to synchronize as with the OneDrive for consumer
Also, it seems there has been big improvements in the performance as after about 3 hours synching my OneDrive for Business, almost 50% has been already done (with the previous version it took between 1 1/2 day and 2 days to get it synchronize with the same amount of data)
Last but not least, it seems you can also add multiple business account as the button Add a business account is still available after adding mine. I did not tested it yet but definitively will.