Hello there,
I would like to know if with the integrated graphic cards of the 13 inch, is it enough to use as a main post processing machine connected to an external display. I am buying this machine for the next 4-5 years. In a way, I think the 15 inch would be better, but with the money saved, I could buy a nice monitor. (currently have dell u2312hm)!
We don't know yet if the 13" will allow 16GB of ram. Is 8GB enough for the next few years? what about processor speed vs 15" (quadcore)? Of course, the 15 will have a faster graphic cards too...
Dilemma..
The 13 and 15 really service two different markets.
Portability (13 )> 15): They're both relatively light compared to your traditional notebooks, and I never felt that the 15 was very heavy... but it was bulky, and definitely a bit more to lug around. If you're going to travel frequently the 13 is definitely better than the 15.
Power (15 >>> 13): Don't be fooled by their processor speeds, as the 13 is dual core, and the 15 is a quad core which is very considerable in terms of performance. The 15 also has integrated graphics, which is good if you plan to do anything more than very light gaming. However, real world benefits of these tend to relate more with what you will be using.
I'd really say if you're main purposes are going to be browsing, watching videos, messaging, word processing, home/hobbyists photo/videos, extremely light gaming the 13 will be a great machine. They both sport solid state drives and most of these functions are going to be near instant. The 13 will have plenty of power to power a 2560 display (current top tier), but may be sluggish when the 4k displays are released.
The 15 becomes a game changer if you do any moderate level of gaming, do really computational heavy stuff such as frequent video editing, compiling for programs, etc. They'll also be a little more capable given if you consider upgrading to a 4k display in the next few years.
In many ways computers have really exceeded the requirements for most software for your average, and slightly above average user. That's why they're focusing on longevity (better battery life) over performance -- so don't need to be as concerned about it being outdated in a year or two because you got the lower end model. That's why so many people with 2008+ dual cores, and a SSD are still quite happy with their machines -- because in every day use there isn't much of a improvement almost 6 years later.