In my opinion, one of the worst aspects of brewing beer is having to bottle it. First you need to either purchase or collect a large number of bottles. Then you need to clean the bottles and potentially strip off a bunch of labels. Next you need to rinse and sanitize your bottles. After that you need to add sugar to the beer (hopefully getting the quantity correct for your style) and then fill your bottles. Finally you cap the bottles and then you must wait for the beer to carbonate in the bottle hoping that it fully carbonates and if so that it does not explode your bottle from over carbonation. Knowing how easy it is to keg, I doubt that I will ever go back unless it is for a specialty batch where the bottle adds aesthetics or the ability to age the beer in a way that would be difficult to achieve via kegging.
For the folks who are new to home brewing, here are some of the benefits of kegging your home brewed beer over bottling it. When you keg your beer, it is ready to drink faster than bottled beer. There are a variety of techniques available for carbonating your beer with a Co2 tank and some methods can have your beer fully carbonated in a matter of minutes as opposed to days. Additionally, when you keg your beer you can carbonate to any level you desire. Perhaps most importantly is the time savings. When you keg, you only need to clean and sanitize one vessel as opped to 20 or more. Kegs are also easy to store and far less fragile than a glass bottle.
If you are looking to start kegging your beer for the first time, there are some great starter kits available that will provide you with everything that you need to get up and running. Here is a great place to start: