Personally, I think that 27" is too big for a 1080p primary monitor.
Think about it this way, 1080p is actually the resolution 1920x1080. That is a pixel count. It literally means that you will have 1,920 pixels across the screen side to side, and 1,080 pixels from top to bottom. That is true no matter if the screen is 20, 24, or 27 inchs. So, in order to have the same number of pixels on a 27 inch screen as a 20 inch screen each of those pixels must be larger. The larger the pixels the more ‘fuzzy’ or pixilated the image will look.
Personally, I think that at 24 inch it is acceptable, but at 27 inch I need to sit farther from the monitor to get a decent image. That means I’m not really gaining anything from the larger monitor.
In the end the best way for you to know for yourself is to go look at some.