Re: Do any major apps actually use this?
Going by what Xamarin's customer reference page says, their typical customer is someone who has a background writing MS Windows software and is just getting their toe wet in writing mobile apps. In other words, they know C# and don't want to stray out of their comfort zone while learning a new language. You might get somewhat serviceable software that way, but you're not likely to get world beating software.
I will take their "755,000 developers" number with a very, very large grain of salt. Given their eye watering prices, if they actually had that many paying customers then given the hype surrounding everything in the mobile industry they would be a multi-billion dollar company. Since I haven't heard of any such suggestions (it would be pretty hard to hide if it were so), then I'm going to take a guess that they are counting downloads of the limited functionality free version.
Their FAQ only claims 15,000 paying customers, although they're a bit vague on the difference between a customer and a developer. If we take it as meaning that one customer equals one developer, then only about 2% of the people who try it end up doing anything serious with it.
I suspect that most of their "developers" are in fact just traditional MS Windows developers or hobbyists who downloaded the trial version to try to make "my first phone app". Of course, there is probably a lot of double counting involved, with the same people downloading multiple new versions or when the 30 day trial ran out.
I followed the original development of Mono back before Xamarin existed when they were simply part of the server group at Novel developing Mono as a competitor to DotNet as a server side and desktop system. Novel felt they needed their own "platform" in order to be a real "full stack enterprise vendor". Every six months or so the Mono team would be hyping a new target market for Mono when the previous plan failed to find a flicker of interest amongst developers. When Attachmate bought Novel, Mono was dumped and the newly unemployed Mono team found venture funding to create a start-up for the newly hot mobile app market.
Where I have heard that Mono has had some interest though is with a few of the large or medium size game developers who were porting existing PC C# game code to mobile and console apps. Game developers felt that Microsoft was screwing them over on licensing terms and costs (which were not the same as for the PC). These companies aren't Xamarin customers though.
Personally though, I think that if someone wanted to get into the mobile app field then learning a new programming language is the least of your worries. I think you are better off sticking with the mainstream languages (Java, Objective-C, Javascript) on the mainstream phone platforms (Android and Apple) where you can find all sorts of tutorials, help forums, libraries, and everything else you'll need to orient yourself in an unfamiliar environment. Going with something which isn't commonplace in mobile is asking for pain, since you will have a hard time finding examples to crib from when you are starting out.
Biting the hand that feeds IT
