We have just finished a very data intensive app written in MonoTouch. The app accesses SAP data, through a middle tier, and exposes this on the app. It also allows direct updates from the app to SAP, again through the same middle tier.
We are in the process of porting this to Windows Phone and Android using MonoDroid.
It took me a while to convince the boss that MonoTouch was the way forwards, and we tried a few different products beforehand including jQuery mobile, ExtJS and Obj C.
The time I was trying to convince him was the time of the Attachmate acquisition and it looked, at times, like MonoTouch was doomed. Luckily for us (me), Xamarin rose like the proverbial Phoenix from the flames, and they have continued to develop Mono* to what it is today.
As a C# developer (and Mono enthusiast) the main win over Obj C or any of the HTML/JavaScript was the fact that I could use C# to get the job done. The documentation was very good, and when the doco didn’t quite cut it (recently been updated) the community did.
The IRC channel is very active, with Xamarin employees and community evangelists always willing to help or provide insight into a problem. As are the mailing lists.
Another plus are the Eco-systems which are growing around MT. MT.Dialog makes developing Table based UI’s an absolute breeze compared to the XCode equivalent. Couple with this the .Net BCL which is, admittedly a subset based on Silverlight, but it has everything from Serialization, Email to Cryptography etc… If .Net doesn’t cover it, or there isn’t a specific Mono* project, you can still use ObjC plugins with your MT code.
I disagree that MT has ‘yet to prove itself’ as a proven platform. We are using it, and whilst we are a relatively small company, there are lots of larger companies also using it. A few of the apps showcased by Apple in the TV ads here in Aus are, reportedly, written in MT.
In order to remain objective, the 2 ‘cons’ of MonoTouch for me have been that you still need to be able to read ObjC (though, tbh, I don’t see this as a con… As a ‘C#’ developer I have to be able to read and write a plethora of languages anyway) and the fact that, historically, MonoDevelop has been a bit buggy. The major bugs appear to have been squashed and, with it being an open source project, you can always fix them and help the rest of us!
To answer your concerns:
- We will have to store quite a lot of data on the client
Use the System.IO classes of .Net in C#. If you are unsure of these, MSDN has oodles of examples (MT hides the iOS implementation of file storage)
- The client wants the app to work offline
they can all do this, but a Native app is always going to feel better in my opinion.
- Our skill set is very much web development C# ASP.Net. Definitely not Objective C
MonoTouch is C# – play to your strengths and have an app in weeks, not months!
My 2 pennies! I would not hesitate to choose the same route again, again and again.