If you start using lesser and lesser known services, the greater the potential threat of odd limitations (SkyDrive's 2gb file size limit, for instance), and especially apparent, a greater surface area for compromising someone's stuff. Trusting 7 companies with data, each secured with a (hopefully different) password is just too big of a risk to practically take. I'm slowly switching to Google Drive for most of my important stuff (I have my eclipse workspace in Dropbox) as a result of two factor and a proven track record of not being compromised. I keep raising the point, but Dropbox has already made this mistake once (http://news.cnet.com/8301-31921_3-20072755-281/dropbox-confi...). Though they're very likely more secure as a result, I'd be hesitant to trust any company lesser known than them for security.
When it comes down to it, a lot more goes into choosing a space provider than just the amounts offered free - making a decision on that alone is bound to lead down troublesome paths.