There are a number of things to consider when you're buying a monitor and I'm not sure how balanced a view that link gives with coments like 'ugly, its looks don’t match its price' & ' just not very nice-looking, which is a shame' when to my mind, performance is the key.
First things first though. Having a seperate mointor gives you more desktop real estate and programs like Lightroom & Photoshop came display different things on each monitor. Even without that capability a laptop will typically have a 1366 x 768 px display where as a 24" montor could be 1980 x 1200 px (some are only 1980 x 1080) which is more than twice the desktop space of a laptop screen. I cant do any serious editing on my laptop - its just too small & also has viewing angle issues - see below. Some 27" monitors give you 2560 x 1440 (beware some are still only 1980 x 1200) which is 3.5 times your laptop. So size is important but not all 24" or 27" monitors are the same.
Next consideration is the technology TN, VA or IPS. Your laptop scren is almost certainly TN technology. When you view it at different angles the colours & brightness will change - not good for photo editing. Better photoediting monitors should be IPS panels.
The third consideration should be wide gamut or not. Non wide gamut monitors, which is the majority of them have a color gamut that matches the SRGB color gamut. sRGB color gamut is not as wide as Adobe 1998 version, & Lightroom uses Pro Photo which is even wider. Some of the Adobe colour space outside the sRGB colour space can be printed via your inkjet printer. As a result, your camera can record colors and they can be printed with your printer. However, you cannot see them on your monitor if you do not have a wide gamut monitor. But if you never print your images & they are only viewed digitaly (via projection or on the web) then there is little benefit in wide gamut or Adobe RGB.
Have a look at this article
http://www.color-management-guide.co...o-editing.html