Windows Desktop - Yes
iPad - Yes (via Lightroom mobile)
S5 - Soon (via Lightroom mobile)
Note, you must have the subscription version of Lightroom to use LR mobile.
Lightroom 5 is supported in Windows 7 or newer. You will be able to use Lightroom Mobile on the iPad, but Lightroom Mobile is not yet supported on Android devices. That support is suspected to be added sometime in the future. Also, take note that you must have a creative cloud account in order to use Lightroom mobile.