What about markdown? As long as the service is new, I would be scared of having my CV depended on your app. Yes, I know LaTeX, I also know it's a pain to set up if you are applying "non standard" formatting.

By the way, I don't know where are you from, but this tool looks cool enough for Nordic countries. In particular, you could target easily carrier centers in Danish universities (http://bss.au.dk/knowledge-exchange/career-centre/). These centers offer free advice for students' CV. I see this service being advised or even used there (like the students upload his CV on the system and gets help virtually).