I will chime in too.
I have 3 desktop type machines. From oldest to newest:
1. An HP 2000 with an AMD E-300 Processor, 320 GB Hard Drive, 2 GB DDR3 RAM (I installed an additional 4 GB), that came preinstalled with Windows 8 and got upgraded to 8.1 (more on this later)
2. An Acer C720-2827 (Chromebook) Chrome OS, Intel Celeron 2955U processor, 16 GB SSD, 2 GB DDR3 RAM
3. An Acer CXI-4GKM (Chromebox) Chrome OS, Intel Celeron 2957U processor, 16 GB SSD, and 4 GB DDR3 RAM.
To begin, my HP was struggling to do common tasks. 4-5 Chrome tabs open and a couple Hangout messages. For any that know some of Hangouts Easter Eggs, there is a /pitchforks command that will send an 8 bit .gif through the bottom of the screen. One of the guys launched that Easter egg...and promptly froze my PC. I had to force a shutdown by longpressing the power button. This was after I got the upgraded RAM.
This incident (along with the general slowness of 8.1) prompted me to try a Chromebook. Most retailers have a 14 day return policy, so I figured, why not? Enter the C720. Like B. Diddy said, fast boot times. I clocked mine at about 12 seconds counting the time to type my password. Since Chrome is relatively light, the battery had an average off charger time of about 5-7 hours (partially due to the smaller screen, I will admit). My HP needed to be plugged in at about 2 hours, if I used it lightly.
I became so impressed by fast updates (downloads take about 10 minutes) and the reboot and you are updated. My HP started to become a dust collector. Fast forward about a year to a few weeks ago. I turn on my HP so that Windows can update. Behold, 32 updates... I was like, 'Ok, I haven't turned it on in a while. I will make it a habit to do so once a week to at least stay on top of it. I started at 9 AM, and got done about 6PM. I thought, 'Ok, no more of this. Staying up to date will be much shorter.' Nope. The following week was a 14 update week, and took over 5 hours to do. I finally threw in the towel and installed Linux Mint, and it is a much better machine by far.
About a week ago, I invested further into Chrome OS by getting the Chromebox. Basically the desktop version of the Chromebook. And I really like it. The 4 GB of RAM is noticeable, not by much but the Box seems more responsive than the Book. I am quite pleased.
During my time with the Book, I realized how much I just surf the net, and don't really need a large on board storage like a PC would. I use Google Documents and Sheets, and they are stored on Drive. I am finding less and less reason to even boot up the PC, although Linux Mint is much more enjoyable to use.
Overall, here is why I like it:
-Update and boot up speeds.
-I am already a Google user, so there is already a familiarity with everything.
-Security. Basically this is like an Android device. Everything comes as an app.
Depending on how you use a machine, you might be surprised by what you can do with these.