Mozilla revealed that Firefox 4 will finally be ready on Tuesday, March 22nd.
The team has concluded that Firefox 4 RC1 will become Firefox 4 final, unless they discover any new major issues over the next couple of days.:
Firefox 4 RC1 has received a very warm welcome; it's time to make a decision to ship. As of now, there are no known issues that would stop us from shipping RC1 as final. At the conclusion of our regular 11:30AM triage session on Wednesday, March 16th, release drivers will decide whether to ship RC1 as Firefox 4.
March 22nd is the day we would ship. Both IT and Marketing have indicated that March 22nd is an acceptable final launch date. If at any time we discover issues that would block final release, we would issue an RC2 as soon as possible, reset the ship date, and communicate to everyone.
All my best,
After this release Mozilla will speed up its development pace, Firefox 5 is expected to arrive just a couple of months after the launch of Firefox 4.