I've used a Chromebook, the C720 4GB model, as my primary computer since last November, I love mine.
Granted, I don't need to do any kind of photo/video editing, but if I needed to do some light photo editing, there's Chrome Apps available. Not to mention, you can dual boot Ubuntu and run GIMP.
As for ChromeOS, it's great for the intended purpose... the internet. That's all I needed a laptop for and it does it very well, it was inexpensive, it's fast, boots quick, etc. You can torrent, there's Google Docs, and so on. All my music is on Google Play Music, so I don't need iTunes or anything like that.
It's not a one size fits all.. so if you need a specific Windows program it's not going to be ideal or if you need to run Photoshop, but for many I'd say it's exactly what they'd need out of a computer for a really great price.