Cloud storage provider Box is offering 50GB’s worth of free storage for users who sign up to its service in the next month – twisting the knife further into rival Dropbox, whose service went down over the weekend.

Dropbox hit the skids after what VP of engineering Aditya Agarwal described as a routine server upgrade, with a bug installed on active servers bringing down the show.

While Dropbox was at pains to insist that everyone’s files were safe, it’s fair to say the news will have affected the company’s reputation. And in a not coincidental move announced yesterday, Box is opening up 50GB of storage for new customers, as well as rolling out a new iPhone and iPad app.

“We’ve overhauled our app to make it super-fast, simpler to use and more immersive,” wrote David Still, Box VP mobile products in a blog post.

“The result …