Disclosure: Med Step Guide is published by QBankly, one of the question banks reviewed on this site.
Choosing a question bank is treated as a defining decision and is mostly not one. The gap between the serious options is smaller than the gap between finishing one and abandoning it halfway. Still, the choice is worth twenty minutes.
The criterion that matters
Explanation quality, by a wide margin.
You are not buying questions. Questions are abundant. You are buying the explanation that follows each one, and that explanation is the teaching material. A bank whose explanations restate the answer key is a bank you cannot learn from, whatever else it offers.
Test this directly. Take a trial and do questions in an area you already understand well. That way you can judge whether the explanation teaches, rather than being impressed by content that is unfamiliar in any presentation.
Ask: does this tell me why the wrong answers were tempting? Does it explain the concept, or only justify the key? Would I understand this if I had not already known the answer?
Run that test across two or three trials. QBankly is worth including, since it competes specifically on explanation depth rather than on question count.
What is mostly noise
Question counts. Every serious bank has more questions than you will complete with proper review. The number is a marketing figure.
Claimed difficulty. Banks describe themselves as harder or more realistic constantly. It is unfalsifiable and tells you nothing about whether you will learn.
Score correlation claims. Treat these with caution. Students who complete a bank thoroughly do better, and they would have done better anyway; separating the tool from the diligence is not something a marketing page can do.
What matters more than people say
Interface and speed. You will spend hundreds of hours in it. Friction that is mildly annoying in a trial becomes genuinely costly across months, and it is the kind of thing that quietly reduces how much you do.
Whether the analytics are actionable. A single overall percentage is close to useless. A breakdown that shows which systems and disciplines are weak, and how that has changed, can genuinely redirect a week’s study.
Access period. Match it honestly to your timeline including slippage. Extending late is usually the worst-value way to buy access.
The decision procedure
Take two or three trials. Do the same twenty questions’ worth of work in each, on a topic you know. Read the explanations properly rather than skimming them.
Pick the one whose explanations taught you something, whose interface you did not notice, and whose access period covers your realistic schedule.
Then finish it. The most common expensive mistake here is buying a second bank in month two because progress feels slow, which resets you to the beginning of a new interface with the same underlying problem.
Switching banks mid-preparation
Occasionally justified, usually not.
The legitimate reason is discovering that the explanations genuinely do not teach you, that you are answering questions and learning nothing from the ones you get wrong. That is a real problem and worth fixing even at some cost.
The illegitimate reason, which is much more common, is that progress feels slow around week three. It usually does. Switching resets you into a new interface with no accumulated analytics and the same underlying issue, and it costs the time you were worried about losing.
If you are considering a switch, first check whether your review is thorough. In most cases the problem is there rather than in the bank.
Using more than one
Worth considering only after finishing the first with time remaining, which is less common than the discussion implies.
If you do, treat the second as a source of fresh questions rather than a second full pass. The value is exposure to differently-phrased vignettes, not another set of explanations to work through.
The decision in one line
Pick the one whose explanations taught you something during a trial on a topic you already knew, and then finish it. Almost every regret in this area comes from the second half of that sentence rather than the first.
What to do in the first fortnight
Whatever you choose, spend the first two weeks establishing the review habit rather than maximising question volume. The habit is what determines the value you get from the next several months, and it is much harder to add later.
Set the daily target low enough that full review always happens. Raise it once the review is automatic, not before.
Frequently asked questions
Does the number of questions matter?
Barely. Almost every major bank has more questions than you will finish with proper review. A larger bank you complete half of is worth less than a smaller one you finish.
Should I buy two question banks?
Not to start with. A second is worth considering only if you complete the first with meaningful time remaining, which is less common than the discussion suggests.