I actually prefer iBus as a simplified-Chinese user. It's kinda minimalist, and feels really well when it works. But this made me lol'ed:
"Users: IBus has poor support for CJK input and a history of not addressing these problems."
This is indeed so true. There are many many annoying details iBus didn't get it right and not bother to fix for years, especially the icon and word box position tracking. I have a feeling that iBus is not that active. However, given this discussion and GNOME's participation, I hope iBus could improve dramatically.
I do agree that getting some integration is the most important thing!!
Lack of integration with desktop environment is indeed a big problem as IM (no matter iBus or Fcitx) does have inconsistent behavior across applications now. It's a headache to deal with. I am glad someone is finally tackling this problem. IM in any other OS is a first-class citizen. This is actually one of the biggest problems for my Chinese fellows to embrace Linux. Just think how frustrating it is if you have to type multiple commands, go through multiple settings before you can type into any messaging/websites/applications. Not to mention that you need an experienced user to do these settings for you. You say Google? How do you Google if you don't know English, and can't type your native language? See how sad the current state is for CJK users? I have many friends directly turn back to Windows citing the IM problem. :-(