A 27" 1080p monitor is not a good choice for everyday computing in my opinion. When you look at a 27" monitor from a normal "computer use" distance (like sitting at a desk), the pixels will appear very large and blurry. Because there aren't very many pixels in a 1080 monitor, you won't be able to display very much information.
A 27" 4k monitor will be much sharper than a 1080p monitor, but you still won't be able to display very much data. You computer essentially treats a 4k display as a 1080p monitor where each pixel is now made up of 4 pixels. Images and text will be sharp, but the UI elements will still be the same "size" as they would be on your 1080p monitor.
Furthermore, I find 30Hz monitors hard to look at for long periods of time. Some people are not bothered by the refresh rate, but I find that I need 60Hz or I start to get a headache.
The website The Wirecutter is a great source for beginners buying guides:
If you want a 27" display, please read this guide. It will give you a great beginners overview of the options out there:
http://thewirecutter.com/reviews/best-27-inch-monitor/
I have used a 24" display for 10 years of professional drafting work. If you think 24" is enough for you, read this guide:
http://thewirecutter.com/reviews/best-24-inch-monitor/ (you'll save a lot of money over a 27" display)
If you absolutely must have a 4k display (which seems like overkill for you), read this guide:
http://thewirecutter.com/reviews/best-4k-monitors/
