Kegging just fits the whole brewing process. I REALLY enjoy brewing. I brew two to three times a month. I would brew more but this by far surpasses my consumption and sharing levels so bottles are working their way back into the process. I use the kegs as secondaries to dry hop in, as bright tanks, aging and conditioning, etc. They are easier to work with and store once you get past the primary fermentation in a carboy or bucket. And then the best part, which is serving awesome homebrew from them! I have started utilizing three gallon kegs and bottling the remainder of a five gallon cornie with some brews. Both are easier to transport for sharing and enjoying away from home. It just depends on the situation. I have to say the reaction and cool factor when showing up with a keg to share is always awesome!
Whether your kegging or bottling, the cleaning process in brewing is I think the biggest challenge. While I think I can always improve on in my brewing processes, I have started to spend more time on making the "clean and sterilized" processes better as well.