My opinion about this:
There is a difference between a project that is in use (like Firefox)
and a proejct that has no use except showing how far it is.
For a project that is in use, there is a benefit from a shorter release
cycle (as long as it's done thoroughly), due to the fact that users
demand bugfixes, to improve their "working experience".
A project like reactos can only show "look, this is what we have so far,
it still doesn't work".
A too short release cycle can result in too few actual changes, and
people don't really see many improvements.
Also release can become boring (yet another release without major
improvements...)
Another final disadvantage is that heavy changes are really hard to get
in in a tight schedule.
After a release devs might be tempted to rush their changes in as soon
as possible, possibly causing multiple major changes being comitted at once.
Therefore I would prefer releases in a multiple month cycle. Every month
or every 2 doesn't seem to be reasonable for our project at the moment.
Just my 2 cents,
Timo