Here is a thoughtful assessment of Apple's subscription model announced today. If you can ignore the fact that the author is a known Apple-fan-boy, the assessment makes a ton of sense and is relatively non-bias. (With the exception of a brief uncalled for zing at Google.)
Although I do not see how AAPL's current enforcement would really hurt or affect services like Netflix, Sling, Hulu etc. Their apps do not provide the subscription, they are gateways to the service. For instance, the updated Netflix app would no longer be allowed to link to Netflix.com if not a member. Instead it would link to the App Store Subscription. Any new member can still sign up for a subscription from the website, then use the app. But if a new member signs up using the iPhone App, then Apple will take its 30% cut. So these services can either not promote new membership through their app or offer it and risk the 30% cut.
If you are invested in AAPL, it is a worth-while read.