The company, facing accusations that it copied the design and some features of Apple's iPad and iPhone, said the Galaxy Note 10.1 would be a "game changer" from rival tablets, on which users usually only view one application at a time.
The device can have two apps active on a split-screen, while an 'S-Pen' seeks to solve tablet and smart-phones' sometimes clunky keyboard and input functions by allowing users to write and sketch on the screen.
Analysts, however, were sceptical of its ability to make inroads into Apple's huge lead in the tablet market given plans to price it at $499 for 16 gigabytes of memory and WiFi-only - the same as the iPad.
"When you look at the price and overall consumer awareness about Samsung tablets, it's not likely to be a big success," said Park Young, an analyst at Woori Investment & Securities in Seoul.
"Tablets are getting cheaper and even Apple is rumoured to be preparing a cheaper iPad. Consumers also tend not to spend much on tablets any more as smartphones can do most of the entertainment functions that tablets offer."
Marc Chacksfield, deputy editor at British tech website TechRadar, said that, while the new tablet had some positive features, it felt cheaper in the hand than the iPad and might not win buyers over if priced similarly to the Apple product.
"Couple this with an influx of low-priced Android tablets entering the market (headed up by the Google (GOOG.O) Nexus 7) and Samsung may struggle to compete," he said in an email to Reuters.
GRAPHIC: Apple earnings r.reuters.com/nez59s
GRAPHIC: Samsung earnings (incl Q2 global smartphone data) r.reuters.com/few99s
A jury begins deliberating next week in a high-stakes patent trial launched by Apple against the South Korean firm.
Ben Wood, head of research at analysts CCS Insight in London, said the S-Pen was Samsung's big bet on differentiating its tablets from Apple's.
"It's an area where we expect them to put a huge amount of focus, some of that will be as a result of Samsung's desire to show it is a company that innovates in the light of all the negative publicity from the litigation," he said.
The U.S. debut of the Galaxy Note 10.1, which uses Google's Android software, comes just three months after the second version of Samsung's flagship Galaxy Tab 10.1 went on sale in May. Samsung is also expected to unveil a tablet running on Microsoft's (MSFT.O) new Windows operating system within months.
While Apple has a single 9.7-inch iPad, Samsung's line-up includes products of different sizes - from 7.7 inches to 10.1 - while late last year it created the hybrid phone-cum-tablet, or phablet, category with the 5.3-inch Note, which has sold more than 10 million units since October.
A revamped version of the Note smartphone is expected to be unwrapped in Berlin later this month.
Apple sold 28.8 million iPads in January-June, giving it 64.4 percent of the market, according to one industry estimate. Samsung sold 4.4 million tablets for a 9.9 percent market share.
The new Note 10.1 features a quad-core processor with 1.4 GHz clock speed, a 5 megapixel rear camera and 1.9 megapixel front-facing camera, which also detects the user's eye movements to prevent the device from going into standby mode.
The 32 GB model will sell for $549, versus iPad's $599.
In Seoul on Thursday, Samsung shares closed unchanged at 1.345 million won in a market down 0.05 percent. Shares in Apple closed down 0.1 percent on Nasdaq on Wednesday.