In a blog post, Roku said that Redbox Instant would be available to all U.S. customers who own a Roku 3, Roku 2, Roku HD (model 2500), or Roku LT (models 2400 and 2450).
For $8 per month, users will have access to Redbox Instant's 5,000+ library of streaming movies in addition to four DVD credits, which can be reserved through Roku and picked up at one of Redbox's thousands of physical kiosks.
Netflix is also available via Roku--and for the same monthly flee--but comes with a growing roster of quality original content. And both services are still slightly more expensive than Amazon Prime, which is available on Roku for only $6.67 per month (based on a $80 per yearly subscription)--and that comes with free two-day Amazon shipping.
Basically, if you're a Roku owner who is really into DVD commentary, and you happen to live close to a physical Redbox kiosk, then the service may make sense. For everyone else, enjoy House of Cards.