In my experience with DIT (which is limited) DIT basically reads you First Aid but gives you a few extra tidbits that may or may not be helpful. Sometimes mnemonics, sometimes explanations, sometimes stupid jokes. Sometimes I'll use it with an organ system but I wouldn't use it during dedicated step prep unless you are scoring very low and need some motivation to go through First Aid
If you haven't read through First Aid on your own, it's best to do it with some assistance, I find it helps getting through it quicker (if you are a slow reader like me) and doesn't allow your mind to wander (at least on the first go). But afterwards, I would only use it in areas where you are having difficulty with. For me physiology was the absolute bane of my existence during Med 1, so I completely reviewed all of my physiology with DIT, Costanzo, First Aid and anything I could get my hands on.
What it's exceptional for:
» Behavioral Sciences
» Medical Ethics/Medicine in Society
» The Early Foundations
These portions of the course offered the most new material I had seen before taking my Step. For me this was all new material and I took my time, watched it at the very least 5x and annotated my FA when they said something I had seen in a question or found semi-relevant.
I would recommend going through the whole course at least once in your light preparation stage, for me that was back in February 2015. The course itself shouldn't take more than 2.5 weeks and the rest of the time (1.5 weeks), I would spend reviewing FA, doing questions and gearing up for NBME at the end of the month.
I have to agree with @Ryuzaki here. I know a lot of people bash DIT and say it's basically just someone reading First Aid to you, but it's really not. I found them invaluable and they add structure to your revision, as well as highlight a lot of material that isn't in First Aid (the extra material appears to be from Step Up and also from student submissions of past questions). They add mnemonics and explain physioloical pathways in different ways than First Aid and even BRS Physio (for the nephron physiology lecture anyway, which was a weak point for me).
And like Ryuzaki mentioned, the parts on Bio-Stats, Ethics and Behavioural were gold. They bring out their founder (Brian Jenkins) to do only a couple lectures these days, but you know those lectures are important because they're not in First Aid and have been tested before on Step 1.
But as many have said before, the best part about DIT is probably that it gives structure to your revision and forces you to stay on track. I don't know if I would use it during dedicated but I used it in my light prep stage too.
they just read FA to you, if I remember correctly, the explanation is minimal at best. Is it helpful? probably, because it it nice to have something guide me through First Aid. It would be good if you are not self-motivated.
But if you are asking if is it worth the $$$, then the answer is a resounding NO. If you have to watch some sort of video, you should use Pathoma, it actually helps you understand things. It would a much wiser use of your time
I tried it and it was not for me. I actually like watching videos as opposed to reading FA. However, I felt that the better part of my 5 week dedicated study time was spent doing UWORLD questions, outlining them in FA, and reviewing the weak sections of my NBMEs.
That being said I heard something interesting from a classmate who did DIT. He said that DIT does a better job at turning a STEP-failing student to a passing student, than it does making a STEP-passing student into a STEP-acing student. Want to go from a 180 NBME to the low 200's? DIT may be right for you. Want to go from the 220's to the 250's, DIT may not be right for you.
The last bit was from a classmate, but take my knowledge with a grain of salt since I did not come anywhere close to finishing the series.
Thought it was a waste of time. Used it for 6 days then gave up. Lots of people will tell you DIT just reads FA to you, but they're not entirely correct. I completed ~25-30 hours of the videos and there was a pretty decent amount of information that won't be found in UFAP. That said, nothing DIT-exclusive showed up on my exam.
Tend to agree with @junojpeg, better for people who are really struggling.
Edit: Also I've heard DIT has a lecture talking about medicare vs medicaid and physician pay systems? Lol. UW had 1 question about the type of pay structure, but that's not worth your time learning. If you actually got a question like that on step 1 just guess and move on. Most people won't know it anyway.