Google vs. Outlook.com (Calendars & Contacts)

I wasn't sure if I should ask this here or in the Apps & Software section as it really applies to both, but here we go. For someone that isn't tied to any one particular ecosystem (say for instance, a Windows desktop, Android smartphone, and iPad tablet), which do you consider to be better for calendars & contacts: Google or Outlook.com? Neither would be used for e-mail.