Apple's iPad 2 challenger Samsung's thinner and lighter Galaxy Tab 10.1 is now available with retailers in the U.S.

The ultra-thin tablet from Samsung, which brings the goodness of Google's tablet-specific OS Android 3.0 or Honeycomb on a 10.1-inch display, was distributed for free to over 5,000 Google I/O attendees by Google in May.

However, just as Galaxy Tab 10.1 potential customers get ready to lay their hands on the thinnest tablet, it is reported that Apple has upped its legal ante against Samsung. Apple has refurbished its earlier patent lawsuit filed against Samsung. The Cupertino company had filed a patent infringement case against Samsung in April, charging it of infringing patents related to the rectangular design of iPhone and iPad and the use of gestures on the touch-screen. The complaint included charges of patent encroachment.

The amended lawsuit says FOSS Patent, uses stronger language which charges Samsung of being the boldest of all competitors in copying Apple's products. Also, Apple has changed the tone of lawsuit by using words like copied instead of misappropriated which was used in the earlier lawsuit.

The lawsuit names Samsung's stellar products like Galaxy Tab 10.1 and Galaxy S 2 as products guilty of infringement.

Apple bamboozled its competitors by launching its slimmer rendition of iPad, the iPad 2, in March. While competitors like Motorola Xoom were basking in the new found glory of super specifications, Apple tilted the game by making the iPad 2 slimmer, lighter and faster.

Samsung was the only company that took the threat seriously with its vice president Lee Don-joo stating: We will have to improve the parts that are inadequate, Apple made it very thin. The result was two ultra-thin tablets Galaxy Tab 10.1 and 8.9.

Samsung bettered Apple's iPad 2 in terms of thinness and weight. The Samsung Galaxy Tab 10.1 weighs 595g (1.31 pounds) while iPad 2 weighs 601g (1.32 pounds). Also, the Galaxy Tab 10.1is merely 8.6mm (0.33-inch) thick while Apple iPad 2 is 8.8mm (0.34-inch) thick.

Te hGalaxy Tab 10.1 sports a 10.1-inch screen compared to iPad 2's 9.7-inch display. It also sports a better screen resolution at 1280x800 compared to iPad 2's 1024x768.  It packs in a 3MP rear and 2MP front facing cameras compared to iPad 2's 2 MP rear and VGA front-facing camera. However, Samsung achieves all this on a slimmer frame than Apple's.

Apart from these key features Galaxy Tab 10.1 matches Apple's iPad 2 memory and pricing as well. Galaxy Tab comes in similar configuration as iPad 2 - 16/32/64 GB. Samsung's offering is also priced competitively at $499 for 16GB and $599 for 32GB. Apple iPad 2 16GB and 32GB Wi-Fi costs $499 and $599 respectively.

Apple's nervousness regarding Samsung Galaxy Tab 10.1 is evident by the lawsuit filed it has filed against its key supplier Samsung. However Apple could be lucky if the recent reports are true. Engadget reported that Samsung is facing shipping delays which could affect supply at certain retails stores.

It was also reported by Eldar Murtazin,'s Editor in Chief last week that Galaxy Tab 10.1's arrival in many countries has been delayed until August due to Android 3.1 issues.

And while Samsung attempts to clear its supply chain of any bottlenecks, Apple iPad 2 has continued its march. DigiTimes reported that Apple iPad 2 demand resulted in a 26 percent increase in the shipment of 9.7-inch touch panels in May. The shipment of touch panels reached 5.38 million units. Shipment of 10.1-inch display panels grew 37 percent to 986,000 units on the back of Samsung Galaxy Tab 10.1's demand. Currently Samsung is the only competitor which has been able to corner 10 percent share of the global tablet market.

Sales for other tablet makers like Motorola, HTC, LG and RIM have been flat. And thus, they have reduced their investments in the 7-inch and 10-inch tablet segment but have strengthened R&D for Android smartphones where they have an edge until Apple iPhone 5 arrives.

This leaves Samsung as the only iPad 2 contender; in fact the only Android tablet capable of giving Apple a run for its money provided it can iron out the supply issues.