I just completed the Becker qbank and give my opinion. Yes, I am a new account and my experience with this qbank has led me to create an account just to write a review. I have done Rx and Kaplan, but not UWorld yet so I cannot compare.
I will say, the e-coach / e-book lecture part of Becker is good. It's very comprehensive and informative. I used it for biochemistry, immunology, and pharm here and there. It's basically the same as the Kaplan videos but with newer looking diagrams that look nice but aren't always an improvement, especially the immunology ones. I've only dabbled in their physiology, pathology, and other topics, which have been well done, particularly behavioral sciences.
The qbank is frustratingly poor. Sure, there are some questions (maybe 2/block) that are challenging in a novel way, but there are so many questions that are either poorly written, entirely wrong, or repeats that doing the question bank isn't really that valuable for learning new material. Many questions are written with ambiguous questions that have multiple answers. Other questions simply have incorrect information. They do respond promptly to feedback on questions and as a result they have corrected >10 questions due to mistakes I have found.
I wonder how many mistakes I missed that I now considered "facts" and will get wrong on the real deal. By publishing (and profiting off!) an unfinished qbank with tons of mistakes, I believe they are really doing their students a disservice and injustice. There are not just small typos, although there are plenty of those, they are explanations with entirely wrong information.
Perhaps the worst part of the question bank is the explanations to questions. Rarely do explanations contain images, diagrams, or figures. Explanations many times give a few random factoids about the correct answer and then fail to truly explain why the other options were incorrect. For this reason, I do not believe you can use Becker bank as a learning tool as you can rx, kaplan, and (presumably) uworld.
When expressed my concerns to Becker, I was told that there was one person working on the question bank and that their editors are way behind, partly because they are working on a step 2 bank. I doubt the qbank will ever improve to a worthy standard. I will be straying away from their step 2 bank.