Geforce GTX 880M, 8 Go Ram... Is it as good as it sounds?

Hi there

I ordered an ASUS RoG a few days ago, here are the specs:

Intel Haswell, Intel Core i7-4700HQ (Quad-Core 2.4 GHz / 3.4 GHz Turbo - cache 6 Mo)
16 Go Ram DDR3
Screen 17.3" Full HD (1920 x 1080 pixels)
NVIDIA GeForce GTX 780M 4 Go GDDR5
SSD de 256 Go + 750 Go 7200 RPM
Microsoft Windows 8.1 64 bits
2000€


The laptop was about to be sent when I recieved an email warning me of the release of the brand new MSI. That laptop's specs seem to be well above that of the ASUS for only an extra 300€.
Here are the specs:

Intel Haswell, Intel Core i7-4800MQ (Quad-Core 2.7 GHz / 3.7 GHz Turbo - cache 6 Mo)
Screen 17.3 Full HD (1920 x 1080 pixels)
32 Go Ram DDR3
NVIDIA GeForce GTX 880M 8 Go GDDR5
2 SSD mSATA 128 Go + 1 To 7200 RPM
Microsoft Windows 8.1 64 bits
2300€

So, the CPU is better, there is twice as much memory, more space... but what I noticed first and foremost is of course the GPU... a Geforce GTX 880M with a whooping 8 Go of Ram!!!

I canceled my order and tried to know more about the beast, more specifically about the GPU, by looking over the internet...
I found a thread on overclock.net where pretty much everybody agrees on the amount of memory being utterly useless.
Here is a link to that thread:
http/www.overclock.net/t/1456471/vc-nvidia-geforce-gtx-880m-is-rebranded-gtx-780m-has-8gb-memory

However, I also read some different threads about that GPU providing a gain of 15 to 20%

Among other things, I'd like to run Crysis 3 at max settings, full HD at above 40 fps, I'd also like to run the Witcher 3 flawlessly, do some heavy work on Photoshop, etc...


So what gives?
Is that GPU as bad as these people make it sound? 8 Go of Ram being useless, etc...?
Will my computer make any use of those 32 Go of Ram with what i plan to do with it?
Is the MSI worth it compared to the ASUS for that extra 300€?


Thanks for your answers!