I was kind of on the anti-DIT boat for a while too (expensive, I can read FA myself, etc), but after going through the Cardiology videos I think I would recommend it to most people. It's kind of like recommending USMLE Rx instead of just reading FA over and over again. Yeah, DIT basically reads FA too you, but they also organize it a little differently, emphasize certain things, and provide a different media to learn from.
I'm the type of person who learns best from multiple resources and/or by having the same resource presented to me in different ways. Anytime you go through a resource on your own, you get out of it what you think is most important because you will obviously pay closer attention to those things. When someone else presents that same resource to you, you get to hear/see/read what they think is most important and often they provide a different viewpoint on the same concepts.
A really simple example is during the DIT vasculitis video, the guy emphasizes that polyarteritis nodosa is ANCA negative. We all know the c-ANCA and p-ANCA associations and the fact that neither of them is a/w PAN, but having someone explicitly state it is a lot different than just subconsciously knowing it.
So it's absolutely not a necessary resource, but I don't think DIT is useful only if you are unmotivated or undisciplined (like I used to think).
