While Box is not as popular as Dropbox or GoogleDrive, it was enterprise oriented from the very beginning and is probably one of the best cloud document management platforms for businesses out there. Alas, even the best have their own flaws. The number #1 issue with Box is the fact that you can only use it in cloud, there are no self-hosted options. Issue #2 is price. Box Starter plan is only $5/mo, but you are allowed to have only 3-10 users. Box Business is $15/user/mo with a 3-user minimum. And Box Enterprise is a whopping $35/user/mo. Box gets to be pricey fast. If you are looking for a free Box.com alternative, you'll love Birix24.
* Please note that the information may have changed since the publication. For current prices and features please visit Bitrix24 pricing page.