I'm mostly familiar with the Word/Writer couple and there this one shines. Under Vista it is far more stable than my (trusted?) Word XP. By the way, the latter is still quite sufficient for all my needs (on a daily, rather intensive basis): now and then I will still discover features I didn't know off (one of the latest was the kind of batch editing facility for style-sheets, and yes, Kingsoft lacks that one ;-(. Worse, I haven't found anything new in 2007/2010 that would be of any use to me, except for the longer list of last opened documents and an improved (but not in every aspect) pasting control. Their touted banner system maybe useful for newbies but is definitely dreadful for a seasoned user like myself. It just slows me down in my daily writing/editing chores...
I guess M$ isn't absolutely interested in good ol' Word interface any more, otherwise they would conduct some kind of Apple/Samsung war about it: you can really consider Kingsoft's look 'n feel as an almost perfect clone of Office in that respect. And this goes down to the little pop-up windows which, by the way, are the only places where you will notice there are, indeed, some" featurettes" missing... They even added tabbed windows which are still sorely missing in M$'s latest iterations. Vista having killed my desktop hard disk (by a series of BSD's) I had to switch to my portable and its 2010. I inadvertently saved my first texts as docx ones. When I noticed this, I reverted to .doc saving. Would you believe that after tha,t 2010 would bluntly refuse to read my .docx any more (its own standard!), urging me to by a full-featured version, just to be able to do that. And guess who saved my day? Yes Kingsoft Writer! This implies that you can perfectly edit those .docx files here and then save them as plain .doc ones. That's much more than just a read function, since 2010/2007 also edits plain .doc ones.
I use style-sheets extensively and that's where Writer shines over OOo and Libre, which often trash existing Word ones or add tons of unwanted styles. Again, the look 'n feel is almost equal and, more important, Word style-sheets are never tampered with. One drawback: for an reason unknown to me, the styles are not listed in alphabetical order and that's cumbersome. Also, when you click in a text, this will not automatically point to the style in use and there is no grouping on top of the list of those styles you've used before as in XP/2003 (wasn't perfect in Word though), all little things that make work easier and faster. By the way, those" featurettes" are also gone in 2010/2007! I guess that's what M$ calls improving the product ;-((
I would gladly switch to Kingsoft, if it wasn't for the fact I'm in an urgent need of French and Dutch (even German, to a smaller extent) spellcheckers and those are sorely lacking in Kingsoft's suite and/or add-ons (any one a working solution, I've tried some but they didn't work out)!
And as a conclusion I would ask those good people at Kingsoft (and OOo and Libre, especially these two) to stop adding features almost nobody uses - they just make them shine against the competition - but concentrate on seamless compatibility on file and even functioning level, with the(unfortunately) undisputed leader...