If there wasn't a need for new browsers, then people wouldn't make them. Don't use it if you don't want to. No one's forcing you.
If every single browser you listed used a different rendering engine, then I can see the argument that it makes it more difficult to test for compatibility. But a lot of them, including SunriseBrowser, use WebKit, so that's not an issue.
And it looks like SunriseBrowser has some innovative new ideas. The good news for Firefox users is that if these ideas pan out, extensions can easily be made to implement the same features in Firefox.