Samsung Galaxy S3 has been dominating the smartphone market since it May 29 release. However, with several promising smartphones due for an August and September unveiling, S3's dominion may be coming to an end.

Smartphone goliaths in waiting are getting ready to steal Galaxy S3's thunder. Below is a round up of Samsung's top three competing devices.

1. LG's Optimus Vu

Recent reports have indicated that LG is gearing up for a U.S. release of its Optimus Vu by September end. The U.S. version will be LTE enabled as well. Currently, the smartphone has already crossed half a million unit sales in South Korea. Optimus Vu was initially pitted as a challenger to Samsung's Galaxy Note, when it launched earlier this year.

Optimus Vu sports a 5-inch display with 1024 x 768 pixels (4:3 aspect ratio). It will run on Android 4.0 Ice Cream Sandwich and packs a 1.5GHz dual-core Snapdragon S4 processor. The device has 1GB of RAM and 32GB of internal memory. The 8-megapixel rear-facing camera is quite a show stealer as well. An Optimus Vu Pen or stylus also comes with the smartphone. However, the Vu Pen - designed like an actual pen when it comes to shape and size - does not slide into the phone's case and is a separate entity. LG asserts that the realistic pen-like styling makes the Vu Pen easier to use than smaller styluses on other devices.

Information regarding the exact release date, network operator, and pricing details are not available.

2. Apple's iPhone 5

Apple's purported iPhone 5 is currently the cynosure of all eyes and rumors. Apple has stayed mum neither confirming nor thwarting the rumors, but that has not stopped aficionados and tech gurus from speculating.

Rumors indicate that the iPhone 5 will get a screen bump up and will have a 4-inch Retina display instead of the 3.5-inch one. At 7.99mm and 16:9 aspect ratio, it will be slimmer and taller than its predecessors and will sport a unibody design. The phone will also pack in an 8-megapixel rear-facing camera, 1GB of Ram, iOS 6 operating system, a 3D camera, 4G LTE, and NFC.

iPhone 5 is expected to debut on Sept. 12 and will release nine days later on Sept. 21. Pricing and carrier details are unavailable. However, it is presumed that major carriers like AT&T and Verizon will continue to partner Apple. The price too is unlikely to see any fluctuations and should stay around the current mark.

3. Samsung's Galaxy Note 2

Samsung's follow-up to the original Galaxy Note - the Galaxy Note 2 - will feature a 5.5-inch flexible AMOLED screen with 1280 x 720 resolution. UBP or Unbreakable Plane Display technology makes up Note 2's bigger screen, making it one of the sturdiest smartphone displays. The quad-core Exynos processor, which clocked at 1.6GHz will power the device. Galaxy Note 2 will pack 1.5GB of RAM, compared to the original Note's 1GB, and will be available in the 16/32/64GB versions along with an expandable memory option, courtesy the microSD slot. Rumors also suggest that the Android-powered Galaxy Note 2 will come pre-loaded with Ice Cream Sandwich (ICS) and may eventually see an update to Jelly Bean. A 13-megapixel camera with an enhanced sensor will add to the smartphone's wow factor.

The Galaxy Note 2 is slated for an Aug.29 unveiling and is expected to be priced competitively.