I actually like this release model quite a bit: its like transcendence, but with releases compressed vastly:
you have stable officially supported releases
and then unsupported preview (or in transcendence's case, 'beta') releases, for people who like to bugtest & aren't afraid of bugs: this means the 'stable' releases are well, must more polished, and so you cna focus those on as milestones of having features
while the previews are basically bug-finding releases to check for bugs in those new features before they go stable.
*has been betatesting for the last 8 years of his life, and thus is quite competent at finding bugs X3*
There is a reason that the bug reports forum has threads mostly started by me >.>