Benefits of using MacBook Pro with discrete graphics

I'm trying to choose between MacBookPro Late 2013 with discrete graphics card and MacBookPro Mid 2014 with integrated graphics. Judging from GPU benchmark GeForce GT650M has a minor performance advantage upon Intel Iris Pro. Also Late 2013 Model has 2,3 GHz comparing to 2,2 GHz on Mid 2014. The problem is a cost: at my location i can buy this Mid 2014 model for 2300$ and Late 2013 one for 2650$.
My question is: are there any less or more significant benefits of having MacBookPro with this discrete video? I'm ready to pay this 350$ but i don't think 5% of graphics performance worth it.

You already have the answer to your question.

As far as I see it, the dGPU will be only beneficial for demanding games, heavy 3D work...

If you're planning on using Solidworks, Maya, Lightwave, or any 3d creation or CAD application get the Iris pro one. It is significantly faster for those tasks and not that far behind the GT650M-750M for gaming

The iGPU, will reduces the complexity of your system. Eliminates the graphics mode switching. Less power consumption, prolongs the battery life.

On the math side: $2300 vs $2650 is 8.6% or $350.

What can you do with $350?

Buy some software (Games) you always wanted.

Buy USB stick, or External Drive for back ups.

Keep it for rainy days :)

On the other side:

The $350 is not for the GeForce GT650M alone. Check the system specs in more details to find the differences you care about.

My vote would be for the iGPU since it comes with newer model that brings other engineering improvements with it.

The other thing to think about is that you can't tell OSX not to switch to the discrete graphics when a program that would use it is started, and this can also have a hit on the amount of time you get on a battery charge.

Is that also worth a few percentage points of graphics performance?

If you regularly play graphics-intensive games while plugged into the wall then it probably is. Otherwise it may well not be.

Definitely go integrated only. Not to save money but to reduce fan noise. Instapaper founder Marco Arment bought a MacBook Pro with discrete GPU back in 2011. He ended up returning it for a model with a much less capable GPU and considerably lower noise.

The 2.0 GHz, 6490M-equipped replacement model does indeed run much cooler than the 2.3 GHz with the 6750M that I returned. The 2.0 has far less fan noise under normal usage, with the fans only spinning up audibly when the CPUs are under a sustained moderate to heavy load.

The Retina MBP with discrete GPU has similar heat and noise issues.

Less famous Alec Kinnear bought the same MBP in 2011. Someone had brought the MBP to me overseas so I couldn't exchange mine as easily and kept it. Years later I'm still not able to use this computer with the discrete GPU turned on (it's too hot and loud) or with external monitor. I can only use it as a carry around thanks to Cory Krieger's donation-ware gfxCardStatus which enables me to run integrated GPU only.

My girlfriend's 2013 Retina MBP 13" with integrated GPU only on the other hand is quiet. I recommend you save your money and your nerves and keep the hot discrete GPU out of your next MBP.