Apple App Store Vs. Android Vs. BlackBerry Vs. Ovi Vs--.

(MoneyWatch)  While Vic Gundotra, Google's developer evangelist, argues that mobile applications will be sold through Web browsers rather than app stores controlled by handset makers, most mobile apps today are sold through app stores.

Microsoft Windows Mobile (for which there is no app store at this point) aside, Apple's iPhone, Nokia's Symbian, Google's Android and Research in Motion's BlackBerry operating systems all support the open source Webkit or HTML 5 standard, which in theory should make it easy for developers to create applications for all those devices. The reality, however, is somewhat different. William Bereault, director of research and development for Apple App Store mobile apps vendor Never Alone Anymore, told me last week in New York that, "in theory you can port the apps to another OS, but it's not easy," he said.

Never Alone Anymore decided to focus on Apple's App Store, at least for the time being, because Apple provides a familiar payment system for customers and handles back-office work. Bereault also told me that the most recent developer kit Apple introduced this spring includes support for more types of attractive features like localization and notifications.

App stores in general currently have three advantages that trump Web browsers:

• they display apps more simply,
• make it easier for customers to pay, and
• make it easier to code for storage on the device itself.

But all app stores are not created equal. William Volk, CEO of iPhone and Android app vendor PlayScreen, breaks it down like this:

• Apple iPhone App Store:

The good news: Low friction, and even with less than 10 percent of the US handset installed base, it represents over half the mobile software sales. Many titles have sold over 100,000 units. A few over a million. Costs are very low to get into the market.

The bad news: Hyper-competitive. Size matters not. License only matters if you get it right. Users expect the quality and performance level of a $20 Nintendo game in a $0.99 cent title. Extremely complex marketing efforts required to get noticed. Don't try to do a 'topical' title because Apple can delay or prevent publication. Power curve, top titles do most of the sales.

• Google Android Market:

The good news: Not crowded. No approval blocks.

The bad news: The very best selling titles may just be hitting 10,000 sales. Almost no users have opted into Google Checkout. Google MUST add operator billing.

• Blackberry App World:

The good news: Not crowded. Eighty percent publisher share (vs. 70 percent from Apple and Google). Adding operator billing to existing PayPal billing system.

The bad news. Users hate the store experience.

• Nokia Ovi:

The good news: Lots of handsets. More than the rest combined.

The bad news: Lots of handsets without the store installed. Rumor has it that Nokia is cherry-picking the Series-40 titles, which is sad because that market is MEGA HUGE!

• Feature Handsets with carrier storefronts:

The good news: Lots of handsets.

The bad news: Carriers don't want to deal with independent developers. Your cost of getting to the market can exceed $10,000 (Verizon).

I'd be curious to know if any of you mobile app developers have different experiences to share.