Choosing a MacBook Pro for a UI designer?

Question

macbook

The bottom line is :)
The moment has come when I decide to invest in myself. For development in the UI / UX design industry, the Mac OS operating system is required. Because trends make us work in apps like Sketch, Flinto, Principle, Framerjs, etc.
Therefore, I chose for myself two versions of the MacBook Pro 13 Retina MF839 (2015) and MacBook Pro 15 Retina MJLQ2 (2015). The price differs in ~500$. For me, this is a significant amount. Because I'm going to take a laptop for 50% on credit.
My tasks:
- Analysis and audit (serf and documents).
- Wireframing.
- Using Sketch, Flinto, Principle, FramerJS, Photoshop programs (to work comfortably when developing large projects, such as huge online stores, administrative panels and mobile applications).
Why MacBook Pro?
- iMac of good configuration, but expensive (for me).
- MacBook Air is very weak for my tasks.
- I would like some mobility, occasionally taking a laptop to work (at work there is a PC with a Dell u2715h monitor).
- The screen is 15 inches, it does not bother at all and has the ability to work comfortably (for me).
I'm afraid that the MacBook Pro 13 Retina MF839 (2015) with 8 GB of RAM will be too weak for my tasks.
Prompt with a choice.

Answer 1

Macbook 13 will do just fine, at least connect a couple of additional monitors) 15 'is worth choosing only if you work offline very often (a 13-inch screen is too small for design).
Also keep in mind that you will need an external monitor anyway, as some designers complain that working in Photoshop on a retina screen is very different from a regular screen.