Gamers, Start Your Engines! 6 Top Gaming Engines Face Off
Gamebryo/Gamebryo Lightspeed/Creation Engine

The Skinny: Developed by Emergent Game Technologies (with builds by its various licensees); written in C++; commercially licensable as binary or source code.
You Know it From: The Elder Scrolls IV: Oblivion, Fallout 3, Fallout: New Vegas, The Elder Scrolls V: Skyrim (Creation Engine), Warhammer Online, Defense Grid: The Awakening, Civilization IV, Bully: Scholarship Edition, many more
The Lowdown: When most people think of Gamebryo, they think of Bethesda's particular open-world RPG take on the engine. But not only is Gamebryo not an RPG-focused engine, it's not even a Bethesda product. Developed by Numerical Design Limited and later Emergent Game Technologies, Gamebryo is a massive multi-platform development engine, featuring a wide array of genres on the PC, consoles, and mobile devices.
Built on NDL's NetImmerse engine, Gamebryo first launched in 2003. The engine was subsequently updated several times, and later iterations are known as Gamebryo Lightspeed. A highly modular engine, the source code for different builds of Gamebryo can vary wildly from project to project. EGT's latest core build, 2.6, supports all current console hardware and up to DirectX 10.
The familiar Bethesda flavor of Gamebryo is a result of extensive source code tinkering. The mangled script, sandbox shenanigans that we've all come to know and love from from Oblivion and the Fallout games are a result of a Frankensteinian stiching together of multiple seemingly incongruous moving parts. They've since completely overhauled and rewritten the engine for use in The Elder Scrolls V: Skyrim, rebranding it the Creation Engine.
Strengths: Gamebryo's strength lies in its modular nature and access to its source code. The engine is interoperable with many middleware solutions, and the engine is well-equipped to handle complex scripting. This approach makes it ideal for building large, dynamic worlds.
On the Bethesda-specific branch of the Gamebryo evolutionary tree, its latest build, the Creation Engine, has been a major step forward for the graphical capabilities of Gamebryo. Skyrim's sweeping vistas, stunning sunsets, and dynamic encounters are a testament to the improved graphical fidelity of the engine. While somewhat cumbersome to tweak, manually editing values in the Skyrim's .ini file can show off the draw distance, particle effects, improved shadows and lighting, and special effects like bloom and radial blur that the engine can offer.
Weaknesses: Due to its modular access, Gamebryo games are essentially the sum of their parts…at best. With different middlewares, systems, codebases, and scripting languages, conflicts can and will occur, leading to both gameplay and stability bugs that can be hard to identify and remedy.
Bethesda's builds of the Gamebryo engine have many well-known issues. Scripting errors are frequent, leading to broken quests, animation loops, and other far more bizarre interactions that take place on a regular basis. Despite significant improvements, even the Creation Engine has no DirectX 11 features. Lack of an integrated advanced physics and interaction system leads to extensive problems with clipping and collisions.

Not to sound like a horse's ass or anything, but even with all the bells & whistles of Skyrim's Creation Engine, there's clearly room for improvement.
The most daming issues, however, are extensive stability issues in Bethesda's Gamebryo builds. Despite EGT being an industry leader in console-centric multi-core processing efficiency with its Floodgate tech, Gamebryo and Creation's support for multiple cores on the PC is virtually nonexistent. Bethesda's games have also been tragically prone to corrupted saves, crashes to desktop, and poor support for various graphics driver builds.
Coming Soon (speculative): Skyrim expansions (Creation Engine)
Frostbite 2

The Skinny: Developed by DICE/EA, 2011; EA proprietary engine, not licensable.
You Know it From: Battlefield 3, Need for Speed: The Run
The Lowdown: The latest and greatest from EA's in-house Swedish studio, Digital Illusions Creative Entertainment (DICE), Frostbite 2 is the much ballyhooed engine behind Battlefield 3. With Frostbite 2, EA seems poised to expand DICE's powerful platform to beyond Battlefield, already using it in a Need For Speed title, and announcing plans to use Frostbite 2 in non-DICE games, something they didn't do with Frostbite 1 or 1.5.
Though a relative newcomer to the engine creation game, DICE's forward-thinking approach and fresher codebase provide Frostbite 2 with a feature-rich, non-dated architecture that can better take advantage of current and future-gen hardware.
Strengths: Built from the ground up to take care of high-end PC hardware, Frostbite 2 is far and away the most advanced graphical engine available at the moment. Frostbite 2 is perhaps the only engine to fully take advantage of both DX11 capabilities and 64-bit processing power, giving high end PCs a much deserved performance showpiece. The most impressive aspects of the engine are the volumetric effects, ambient occlusion, and light and shadow mapping. These powerful shader and rendering tools and effects create the most photorealistic screenshots to date, and even more impressive results in motion.

No smoke and mirrors here—ok, so there's some smoke, but Frostbite 2 powered Battlefield 3 really does look this good.
Though optimized for 64-bit architecture, Frostbite 2 is surprisingly scalable. Battlefield 3 is still a stunning looking game on relatively low settings—a modest PC can run the game smoothly on the Medium preset and still blow the console versions out of the water.
Weaknesses: Frostbite 2's main weakness is simply its lack of availability. As a proprietary EA engine, there are no plans to license the engine outside of EA internal studios. Though EA is taking steps to expand Frostbite 2's footprint in-house, there are still a relatively small number of titles expected to feature the engine. DICE has also been ambivalent about mod support for Battlefield 3, claiming the engine is too complex for the average amateur modding team. Compatibility wise, Frostbite 2 doesn't support DirectX 9 on PC, so no XP compatibility (though we consider the euthanizing of the aging OS a move in the right direction).
Frostbite 2 is also a key example of the law of diminishing returns. Getting solid framerates on BF3's High settings are easy, but the farther you push into Ultra territory the harder it is to maintain smooth performance. While not reaching Crysis 1 levels of inaccessibility, most gamers won't have the multi-GPU builds required to max out Frostbite 2's graphical capabilities.
Coming Soon (speculative): Mirror’s Edge 2, Dragon Age 3 multiplayer mode , Command & Conquer: Generals 2