Firefox 6 is already on the start position so anyone who wants to try the firefox of the future, should download the preliminary version of Aurora first. Its not a secret anymore that Mozilla pushes for a quicker release schedule for the next browser versions of Firefox after having taken extremely long development time for Firefox 4. Therefore, it was now already the second preview-release of Firefox 6, that has been released so far.
According to the schedule, the final version of Firefox 5 will be released firstly on 21st June 2011 for download, hence, you should not expect too much good news for the time being.