New Elliptical w/ iFit...but is it worth the cost?

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I recently purchased a new elliptical. I opted to purchase the iFit module because it seems neat but it just dawned on me that I still have to shell out more money for the SD cards and so on. I'm thinking of returning it since I don't fully see the benefit of paying out more money for something that I may or may not use.

Does anyone out there have it on an elliptical and find it worth it? I have a bad knee and achillies tendon on the same leg so I can't do some of those crazy routines that's might come with Jillian Michaels' cards so I know I'd have to modify a ton of things. So...do you think its worth keeping and paying out more as time goes on (not only for the cards/download but the $100 annual fee to use their site)?