Quote Originally Posted by Digital Foundry
It was a pleasant surprise not just for us, but also for many game developers out there working on PS4 titles now and completely unaware of the upgrade - a final flourish to the design seemingly added in at the last moment to make PlayStation 4 the most technologically advanced games console of the next gaming era.
Source: Eurogamer/DF

Naughty Dog lead Engine and Graphics Programmer:

John Carmack
I can’t speak freely about PS4, but now that some specs have been made public, I can say that Sony made wise engineering choices.
Randy Pitchford
Thanks for the great event in NY @playstation - Very pleased with the commitment to 8gb of GDDR5 memory. Other specs are beautiful too!
Tiago Sousa [R&D Principal Graphics Programmer at Crytek. Worked on Far Cry, Crysis 1, 2 and 3 + all CryENGINE iterations]
8 GB unified mem as baseline for next tech iterations makes me very, very happy. Fun times coming ^_^
Stefan Boberg (Frostbite Technical Director)
"Dev-friendly platforms FTW"
Johan Andersson
Rendering Architect at DICE working on Frostbite and future DICE/EA games
lots of memory is essential for both the CPU & GPU to create large & alive game worlds

If Killzone was running with 4gb gddr5. Well $#@!. Great move by Sony providing they can shift the hardware come release. Developers seem very, very happy with this.
Epic co founder seemed very happy on Game Trailer's after show

*slow clap*