A lot of points listed below are coming from personal experience due to me having a very similar laptop to the one I recommmended. Lenvo z50-70
First of all I think it is very important to have dedicated graphics card for heavy graphics load like video editing and gaming. In this use case the graphics card is the most important part of the laptop. Also Nvidia has very good technology called prime. The model I recommended has this technology, it uses your integrated intel graphics when not needing graphics performance like when browsing the web. If you need your graphics power like when editing video, the nvidia driver automatically kicks in with your powerfull nVidia card to get the performance needed. With this it is possible to save a lot of power (battery life). I personally love this feature and it works without problems on my lenovo with windows 8.1 and various Linux distros
next up the display is better than on the i7 model but has the same resolution than the g50. Personally I like the full HD screen, it is very sharp and colors are good as well. A good display is also extremely important in this use case especially video editing.
The 256GB SSD makes your whole OS faster and is these days a must. It makes your programs faster and also your editing workflow more fluent.
The processor is very decent and good enough for this use case.
the nVidia GPU is slightly better than the AMD one (http://gpuboss.com/gpus/Radeon-R7-M260DX-vs-GeForce-840M) and I think prime technology just isn't a big plus.
Depending on which OS you want to install nVidia and Intel is the way to go. I personally am not a fan of AMD Hardware because I'm a Linux user, I won't go into detail with this just know AMD can be a giant pain when using Linux. If using Linux, the nVidia drivers work perfectly with ubuntu/debian based distros and are very easy to install.
The only minus is the 4 GB of ram that normally should be enough, if not you can easily upgrade to 8GB for about 30€ (http://www.amazon.de/DDR3L-1600-SO-DIMM-1600Mhz-PC3L-12800S-Voltage/dp/B00IIRSIK6/ref=pd_sim_147_7?ie=UTF8&refRID=1E7S7EWFK87F1EMHJJ1W)
So if you can spend a bit more go with the z50-70 I linked above to get better performance, if not your next best call probably is the AMD model z50. I would not recommend the i7 model g50 because it does not suit your needs at all.
I hope I could help, Tanonic
