They ultimately serve the same purpose, but subscriptions are more limiting. I attached a screen shot of documentation we prepared for our users that explains the difference. I hope that helps.
Subscriptions are report views in the users My content > Subscriptions folder. The Subscriptions folder is hidden from the user. Subscriptions are always named "My [Source Report Name]."
By the way, I asked the very same question in a support ticket when we upgraded from 10.2.2 to 11.x because IBM documentation on this is weak.
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Wendi Lewis
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