I can totally understand the 4.0 bug issue and needing to wait until things calm down. For me however, I have no choice but to use 4.0 due to various necessary features. With emails from Firetank indicating that its only 2 weeks away, I decided to support them even though I couldn't use their software at the moment. However, I perfectly understand about timelines slipping as a developer.
So if you're seeing this Firetank, just know that I and others are eager to use your software with 4.0 even if it is scaled down at the moment. Surely your code can't be as buggy as XCart 4.0 and I'm willing to work around that!