Is anyone on the site in the beta for MonoTouch? What issues have you been seeing with it?
I personally have found it a very nice little system and have just made a small test app with it. The test app seems to startup slowly, but it works on my device so I am happy to be using C# on the iPhone.
If you have access to the monotouch mailing list you will find lots of useful information.
I for one found a couple of issues, mainly with the Interface Builder generating the C# code.
another one was an issue with MapKit where the app crashes.
Constant conversation on issues and ways to work around it are in the list and in #monotouch on the GIMP irc network.