We are currently using Titanium and Appcelerator for mobile platform development? Does the Force.com platform offer a simpler and more productive environment? Our platforms are iOS + Android?
Lots of people are asking about mobile development on Salesforce. While I'm not an expert I have some observations that might be helpful.
Salesforce is a cloud-based, software as a service, programming product with lots of pre-built functionality available out of the box. The prebuilt stuff is mostly sales oriented but there are now tons of 3rd party "apps" that you can buy (some are also free) in their own app store that go way beyond the sales paradigm. These "apps" are all built on top of the Salesforce platform so if you were a Salesforce customer you could create the same functionality yourself without needing any additional tools or software if you had the skills and time. The platform is very robust.
You can also enhance and expand the basic product without doing any programming, but Salesforce now offers a programming language called Apex that is apparently similar to Java or C#?? that gives you even more power.
All of this power, however, is focused primarily on desktop PC users accessing the system with a browser. Salesforce has recently expanded the toolbox to include more features that make it possible to develop mobile-centric apps but the intent appears to be to develop mobile apps that are an extension to the primary function which would still be accessed from the desktop. Whether the apps are native or html5 wrapped inside something else I don't know.
Salesforce is clearly aware of the rapid transition to mobile computing but the business environment is not moving quite as fast as the consumer markets. Since Salesforce is focused mainly on business customers (for now) they are smart to deliver the functionality that market segment needs without adding a lot of features they don't need.
You can develop an Android or IOS app that connects to the Salesforce framework through APIs. You can sell that app on Google's or Apple's app stores ... but you still need a Salesforce account to "get in" and their pricing is not like a basic hosting service so not sure the economics would work out if your business model was all about the app and not about using the Salesforce account for it's primary purpose of automating your business functions.
I don't know what their roadmap for future development is but it will surely include more mobile development capability. Salesforce seems very intent on making things as simple as possible so they may push mobile app development down the "simple" path as well and at some point in the future just decide to turn up the heat in consumer app development but for now, the focus is mainly business.
The problem some people seem to get hung up on is the use of the term "app". Salesforce uses the word to describe a package of functionality that typically includes database objects, screens, data-integrity checking rules and automation to simplify business processes. Of course there is a lot of overlap ... many native mobile "apps" could be described the same way. Bottom line, however, is that the word application was around long before mobile computing was and while mobile users have latched on to the abbreviation "app" they should remember that it isn't exclusive to the mobile domain.