Given that you're in part competing directly with the free, built-in review tools in Github and Bitbucket, you need to specifically show what you're offering that they aren't.
I'd say that our two main differentiators are:
* a clear "to do" list: you know at first glance if there are some commits to review, and the review process is made as simple as possible, not to get in the way of the development process
* code likes - let the author know that some code is good, you like the design etc. Helps to make the reviews less negative, and in the future can be a great knowledge base!
So $25/mo per 5 users to 'like' a line of code, and the hassle of having another website or pice of software to use on top of my normal issue and source management tools. Not really worth it at all when I can just IM the dev and say 'good job, you didn't break the world haha'.
I would say the the biggest value of CodeBrag is that it is a well designed tool that does one thing well; such tools are usually worth their price - at least for the time they save not fighting other tools. Or writing on IM :)
Besides, how often do you say to others that you liked their code? The simpler that is, the more often people will do it.
I've never found myself wanting a like button for code. It's a nice gimmick, but I don't see it providing enough value that would impact my decision to use a product providing it.
It's not all about this "Like" button. There are other things in Codebrag we think can make it worth trying: all your duties in one place (commits waiting for your review, comments and likes from other users you may want to reply to). Also it doesn't stand on your way, no tons of clicking, going through complicated lifecycles and so on.
The to-do list also applies to followups - reactions to your code. You get a clear list of what comments other people had on your code, and if you don't want to work on them right away, there's no risk they are going to get buried in a pile of email.
Not all organisations would feel comfortable hosting their code on GitHub. I can see large companies or those with sensitive code preferring to keep their source code in-house
