Seeking replacement for CloudOn?

Shemademedothis is disappointed: he's just found out that his favourite app hasn't malfunctioned after all but has been closed down. Does anyone know of a great replacement for CloudOn, that allows you to work with (edit, read, etc) Office docs as if you have Office yet is cloud-based, works with Dropbox etc?

He used it on several desktop computers, laptop, iPad, phone; so the versatility was useful. He used it with docs received from students and from a variety of other sources, so again, that ease of use was helpful. .pdf isn't as helpful; he uses a lot of Word, Excel, some PowerPoint docs.

Thanks

Like Office365?

He'd rather not pay ongoing, thanks. (He paid for the app, but doesn't want all the ongoing costs)

He used to have a clever, mobile version but that hasn't kept pace with all the updates.