It's old news but at least now its official: the Android platform has become more popular than the Apple iOS in terms of smartphone market share. So logically we'll take a look at why with a comparison of the leading Android devices against the infamous iPhone 4.
As of yesterday, Apple is no longer king of the castle when it comes to smartphone market share. The Neilsen Company reported Monday that 27% of U.S. smartphone sales in Q1 and Q2 2010 were of the Android variety, pushing past Apple's 23% holding. Perhaps this is simply because the Android operating system is found on multiple phones on every carrier, whereas Apple's iOS is on their sole handset, the iPhone. It's worth noting, however, that all Android devices outsold all iPhones--these numbers do not merely account for iOS4.

Android's popularity seems exponential. With more embracing Android, it seems fairly certain their market share will continue to increase to rival or surpass RIM's 33% lead.

Below I've decided to compare the cutting edge of smartphone technology with the iPhone 4, as the iPhone was the gold standard in previous years. To simplify things, I've broken it down into easily-read pro-con lists.

But first, so we don't get bogged down with rehashing old news, let's state some non device-specific, global facts:

• AT&T coverage is not as expansive or reliable as Verizon or Sprint in the majority of the United States (note: AT&T claims to cover 97% of America…but this is only with 2G coverage).

• AT&T has a limited data plan, other carriers are unlimited.
  

• Android has true multi-tasking (iOS4 only allows a few native applications to run in the background)

• Android handsets have expandable, removable memory beyond the 32GB capacity of iPhone 4.

• The devices listed below will run Android 2.2 (Froyo) by the end of August, which promises 450% speed increases.

• Android displays Adobe Flash content, iOS does not.

• Both App market places will be considered equal (essential/popular applications are found in both--we don't need many iterations of the same thing, do we?)

• All devices listed below are capable of 720p video recording

• All primary cameras listed below will be considered equal, regardless of resolution or sensor quality (the trade-offs between all of them essentially result in a tie with the iPhone perhaps taking the slightest of leads)

• All devices below have a stock processor speed of 1Ghz

• Larger-than-average screen sizes will be listed as both pros and cons as this is a matter of individual taste

Verizon

Droid X:

• Pros: HDMI out, OMAP processor (ideal for overclocking up to .2Ghz extra), Large 4.3" screen, 3 microphones for increased noise cancellation
• Cons: Motoblur UI, Abysmal battery life, LCD screen, Large size

Droid Incredible:

• Pro: Notification method with Sense UI, Smallest Verizon iPhone alternative

• Con: AMOLED screen (difficult to view in direct sunlight), Screen resolution, No video out

AT&T

Samsung Galaxy S Captivate:

• Pro: Super AMOLED screen, Front facing camera for video chat over cellular network, DLNA (wirelessly stream content to DLNA TV's, monitors, computers), Almost identical iPhone 4 processor

• Con: Samsung's notoriously slow updates, No video (HDMI) out unless with $50 cable

Sprint

HTC Evo 4G:

• Pro: Large 4.3" screen, Video chat via cell provider, Kickstand, HDMI out, 4G connectivity, Notification method with Sense UI

• Con: Worst Battery life of any Android handset, TFT LCD screen, Large size

Samsung Galaxy S Epic 4G (by Aug 31):

• Pro: Full QWERTY keyboard, Wireless hotspot feature, 4G connectivity

• Con: slightly bulkier/heavier (think original Motorola Droid), Video (HDMI) out only with $50 cable

T-Mobile

Samsung Galaxy S Vibrant:

• Pro: Super AMOLED screen, DLNA (wirelessly stream content to DLNA TV's, monitors, computers)

• Con: Lacks front facing camera, No hotspot feature, Video (HDMI) out only with $50 cable

For complete reviews and rankings, visit PC World's Top Ten Cell Phones. To root your Android phone and use it to its full potential (loading custom ROM's and overclocking with custom kernels) visit the Unrevoked website or AllDroid.org specifically for the Droid X Root Program.

As always, if I've left out anything, leave it in the comments.