Quite an annoyance:
1. use MS Word to insert an automated index, e.g. a table of contents or a calculated field such as [number of pages], then
2. edit it in oo (Server), that text field gets converted to normal text. And therefore
3. when i go back to word, the automation is gone.
This is especially bad when using things such as automatically updating page references, a standard tool in complex documentation. They are all over our documents.
I totally don't expect oo to support all of the features of MS word, and i appreciate a slim editor. But generally, oo should not break document features that is doesn't support.