You should see some updates to iUI coming soon. We expect a beta of the
next release by September 1st. At and after iPhoneDevCamp, there have
been a handful of folks who have stepped forward to help with iUI, so we
should be seeing more regular releases soon. Stay tuned...
-- Sean
Webapp.net is better and kept updated.
Unfortunatly it is not as simple as iUi and sometimes the technical
design could be simplified.
The asynchronous call for example is way complicated compared to the
iUi one.
Even with that I consider Webapp.net better.
On web form webapp.net is also better : more component (toggle, ...)
A documentation is started, a real one, with examples and explanations
but there is still a lot to do.
The project is not really hosted but put online by the author, so
there is a risk for the future
and this is a barrier for a community to grow around Webapp.net.
I had a look to another one I forget the name made by a spanish guy.
His work is not mature enought and even the demo show some problems.
There is no real doc but some material is written in Spanish so I was
not able to understand.
=> Webapp.net is the best choice right now even if it is not perfect :-)