Wireless carriers immediately announced off-contract prices for the devices that start at $720, high enough to raise eyebrows from some analysts.
Both devices went on pre-order at 3 p.m. ET Thursday on various websites and will go on sale in stores in the U.S. and Canada on Aug. 21.
Sprint immediately announced off-contract prices of $792 for the 32GB Edge Plus and $888 for the 64GB version. For the Note 5, the off-contract price was $720 for the 32GB model and $816 for the 64GB.
AT&T's off-contract prices were somewhat higher, at $815 for the 32GB Edge Plus and $915 for the 64GB version, and $740 for the 32GB Note 5 and $840 for the 64GB model.
The features of the two devices are strikingly similar and don't greatly expand beyond the previous Note 4 or S6 Edge. Several analysts said the new products show mainly "incremental improvements. "
Each device runs Android 5.1.1 (Lollipop) with a Samsung Exynos 7420 Octa-core 64-bit processor. Both have a 3,000 mAh battery for 28 hours talk time, a 16-megapixel rear-facing camera and a 5-megapixel front-facing camera. Both also have 4GB of RAM.
"Pricing will be key for these devices," noted Carolina Milanesi, chief of research for Kantar WorldPanel, who commented, "Wow!" to the early high prices announced by Sprint and AT&T.
Samsung needs to compete against the iPhone 6 Plus with the Note 5, which could mean consumers will pick the one with the lower price, she said. The higher cost of the curved display with the Edge Plus might not give Samsung "enough wiggle room on pricing," however, Milanesi added.
However, Gartner analyst Tuong Nguyen said the Note 5 and Edge Plus prices are intended to categorize the devices at the high end of all smartphones, which he called "halo" products.
"Samsung is going to appeal to the very high end of the market with those prices," Nguyen said. "Samsung's purpose in keeping them high end is to make them seem interesting and viable, but that doesn't bring a horde of consumers over to buy them."
Nguyen said Samsung is also on the right track with making the 5.7-in. Edge Plus bigger than its predecessor, which has a 5.1-in. display. "There's consumer sentiment towards larger screens and there's definitely opportunity there," he said.
Apple's decision to introduce larger screens on the iPhone 6 and iPhone 6 Plus have helped their sales, analysts said. In the second quarter, the iPhone 6 was the biggest selling phone in the U.S., while last year's Galaxy S5 was the second-best seller, followed in third place by the Galaxy S6, which first went on sale in April.
Samsung introduced both its new devices by noting that it first pioneered larger screen smartphones in 2011 with the original Galaxy Note.
Samsung postponed a full announcement of its latest round-faced smartwatch until Sept. 3 at the IFA trade show in Berlin. Samsung flashed photos during a presentation in New York that was webcast showing the device with the name, "Gear S2" instead of the Tizen-powered Gear A as rumored.
Samsung Electronics CEO J.K. Shin also announced the Samsung Pay mobile payment solution will debut in Korea on Aug. 20 and in the U.S. on Sept. 28.
Samsung Pay will work in the two new Samsung phones with in-store terminals that have Near Field Communication (like Apple Pay and others) as well as older magnetic stripe readers and barcode scanners -- technologies that will greatly expand its use in many places. "It's simple, safe and accepted virtually anywhere," said Injong Rhee, executive vice president of Samsung Pay.
Samsung Pay also works in the Galaxy S6 and Galaxy S6 Edge smartphones, which first shipped in April. To work with magnetic stripe terminals, the latest Samsung phones have a copper ring embedded that provides magnetic transmission technology that Samsung acquired from startup LoopPay.
Despite Samsung's enthusiasm for Samsung Pay, customers don't choose a smartphone based on its ability to make mobile payments. "Samsung Pay is more about keeping customers versus winning over customers, giving users who might want mobile payments a reason not to go over to Apple. Remember, mobile payment thus far is not something people have craved for in phones." Milanesi noted.
Samsung also showed a combination physical keyboard and cover, aptly dubbed the Keyboard Cover, for the Note 5 that will ship at a later date. In addition to the Note 5's SPen digital stylus, Milanesi called the Keyboard Cover "slightly confusing." She added, "if you buy the device because of the SPen, then the keyboard is not something you need or want."
James Moar, an analyst at Juniper Research, noted that the absence of a stylus in the Edge Plus shows it is more of a device for consuming media, games and other content than it is for creating content. "They are trying to be more friendly to general consumers," he said, while noting that there are already "quite a few consumer phablets to choose from."
Samsung said both of its devices will benefit from a new wireless charging device that will decrease charging time to two hours on both devices, down from three hours. Details on the wireless charging device weren't immediately available.
In other details, Sprint will sell the 32GB Edge Plus with a two-year service agreement for $349.99, and $449.99 for the 64GB version. The 32GB Note 5 will sell for $249.99 with a contract, and $349.99 for the 64GB version.
With a two-year contract, AT&T's price is $300 for the 32GB Edge Plus and $400 for the 64GB model. The 32GB version of the Note 5 will sell for $250 with contract, and $350 for the 64GB version.