Switch to weave merge?

[John Yates]

Aaron Bentley wrote:

> Bzr's weave merge requires operations that cannot be cheaply performed
> on a knit.  Specifically, it needs to know about deleted lines.
>
> Knit merge, on the other hand, can be performed at decent speeds on a
> weave, or anything else with cheap annotation.

Under what circumstances do the results diverge?  Is one inherently more
powerful than the other?

/john