I've found it to be buggy as well, and I've only written one document with it. When I saved it it removed all the formatting including line breaks. All of a sudden my nicely laid out page with headings turned into one oversized paragraph in plain text
Fortunately I had copied the whole thing to the clipboard because I wanted to test something. So I deleted all the text, pasted, hit save and it crashed.
I then closed that document and opened a new one. Pasted the text, hit save, and it removed all the formatting again!
I tried a few more times, but every time it either crashed or removed the formatting *sigh*
I uninstalled and reinstalled Quick Office after that, but haven't tested it again. If it glitches again I'm just going to consider it useless.
HTC Magician > O2 XDA Stealth > HTC Nike > SE X1 > T-Mobile G2 > Palm pre > HP pre 3