Reviews at the App Store are supposed to provide some measure of social proof. If reviews are fairly positive, chances are it's safe to spend your money. The assumption is that the reviewers share your concerns and sensibilities.
Unfortunately, some people are so far out on the curve you should ignore them.
A single bad review among a dozen positive ones stings me more than it should. Worse, it also influences purchasing decisions. People are naturally conservative with their money, so if there's a shred of doubt they may move on and avoid the risk.
Most people know when a review is bullshit, but it's not always obvious.
Here are a couple things that frustrate app developers and have the greatest chance to impact sales negatively.
The ones that ambiguously criticize standard UI elements
If someone is using an iOS device for the first time, they may not be familiar with the standard controls, gestures, and dialogs.
Someone wrote a review about one of my apps and expressed extreme frustration with one of my screens. I realized they were talking about the standard MFMailComposeViewController (the screen you see when you want to send an email from an app) and had mistaken it for the main screen of my app. We resolved the misunderstanding via email, but he never changed his review.
The problem is that it's not entirely clear what screen he's talking about in the review. A casual window shopper simply sees that there's a seriously does-not-work-as-expected screen in this app, and they move on.
The ones that seem desperate for help, but never seek it
Sometimes, among many positive reviews, someone will barge in with a shocking tale of woe and confusion. They lament the loss of their money and make it seem like they've tried everything.
This is particularly frustrating when, as the developer, you know the person hasn't read the app description, hasn't used the in-app help, and hasn't contacted you.
If you really want help, want a solution, and care about your money as much as you purport to, contact the developer. I once spent 4 hours helping someone recover some data after an iOS update and sync wiped out all their apps. I'll do what I can for anyone having trouble.
I provide in-app contact methods, as well as the support links on iTunes.
These kinds of reviews are confusing because there are others that follow the same pattern and are genuine accounts of a crappy experience. Thankfully, other users will often correct a reviewer in their own reviews, but this doesn't happen enough to negate the problem.
The App Store has some amazing values
Think of all the great pieces of software you can buy for less than the cost of a drink at a restaurant. Even more amazing, if the waiter at the restaurant keeps your glass topped off you're expected to spend more and leave a big tip!
Horrifically, the drink is automatically uninstalled the next time you visit the toilet.
With apps, you get updates for free and most apps are niche enough to afford you a direct line to the developer(s). You can send suggestions and influence the app's development.
Real estate timeshares might be a questionable investment, but investing in a developer for a couple dollars is a great idea.
Developers want to talk to you
I hear from a lot of customers via email. I love reading and responding.
As for the App Store, hopefully developers will eventually be able to respond to individual reviews. This will help correct some of the information asymmetry present in these situations.
