This is a question we get often, with varying levels of friendliness or hostility. And, while folks are looking for a simple answer, the answer is far from simple. A good place to start would be how we handle incoming reviews.
When we get a request for review emailed to us, there are a few barriers before our contributors consider reviewing it.
Ideally, the comic will be a reasonably-sized PDF (under 100 MB) we can download to our servers from Dropbox, Google Drive, or a similar file hosting site, allowing for permissions for others to view. This makes it easier to share with our contributors. Physical copies aren't ideal because we can't share them easily.
Before the comic can make it onto our servers, an editor looks it over to make sure it meets our quality standards. Rough art, lettering, or production quality aren't always a deal-breaker, but with so many comics sent our way, it's important to have some level of quality filter.
Assuming it makes it this far, the comic is moved to our servers, where our contributors can look it over for a potential review. We're all volunteers, so each of us reviews what piques our interest. That being said, comics that have unique hooks, art, genre mashups, or that already have a lot of chatter surrounding them tend to do well on our site. Superhero comics, comics lacking in professional polish, or those that seem derivative of what's already out there tend not to be covered as much as others.
Last, we may decide not to cover something if we can’t provide a balanced review based on significant craft or content issues. Also, sometimes, a comic may not resonate with a reviewer, and that contributor will bow out of covering it. It then goes back to our pool of review copies for someone else to choose.
We don’t let creators know when we choose not to review a comic because we feel it’s not up to snuff or because a writer would otherwise give it a negative review. The few times we’ve done this in the past, we were met with some uncomfortable conversations. We understand there are some creators who would like to know what they can improve on, but that is a job editors are better-suited for during your project’s production. I know reviews are free where editors often are not, but it’s not the purpose of a review, and the time we’d spend giving you free editorial advice is time we could spend reviewing other comics, and not within the volunteer job description.
And that leads me to those “uncomfortable conversations” I mentioned earlier. Most of them boil down to some hard truths it’s important to know about critics and websites:
We don’t work for you. You don’t pay us. We don’t guarantee reviews of your work.