The iPhone 4 comes out tomorrow although Best Buy, Wal-Mart and Radio Shack reportedly wont have the device available as planned  and hopeful users may be wondering how much how it stacks up to some other smartphones. Indeed, in an economy that remains uncertain, committing to pricey communications contracts for a device without tethering options and with walled-garden apps can be a concern. If thats the case for you, consultancy BillShrink says the iPhone 4 probably isnt the way to go.

Thats because the most economical use of the iPhone 4 appears to be the minimum voice/data/text plan. And now that AT&T Inc., the exclusive iPhone carrier in the United States, has ended its unlimited data plans, the minimum option holds little value for most subscribers. Most people have ramped up their data consumption by 3.5 times in the past 15 months, said BillShrink, and the minimum AT&T plan falls well short of that usage. New customers will have to pay $15 for a 200MB plan or $25 for 2GB. For most users, 200MB is too-little capacity and 2GB is too much.

Besides, the iPhone is still 3G-only. On the other hand, for example, the HTC EVO 4G is, well, 4G; and it runs on Google Inc.s Android operating system. The EVO 4G sells through Sprint, which partners with Clearwire for 4G access. And even though 4G coverage is limited and costs an extra $10 for the data surcharge, the EVO 4G acts as a mobile hotspot and connects up to eight devices. Apple wont allow the iPhone to tether to the iPad. As BillShrink points out, Why pay for AT&Ts questionable $25 3G connection on your iPad when you can just Wi-Fi-hotspot with your EVO 4G? Plus, Sprint, unlike Apple, continues to offer unlimited wireless plans.

On top of all of that, the iPhone 4 operating system is much less open than Android. Apple tightly controls the apps it allows on its devices while Android promotes developer freedom and maintains much less strict oversight of content.

The iPhone 4 became available for pre-ordering last week. Demand was so great that Apple servers crashed and Apple, AT&T, Best Buy, Radio Shack and Wal-Mart all are saying many pre-orders wont be filled on tomorrows launch date as expected. Apple cut off pre-orders at 600,000.