Depends very much on the airline and the circumstances.
My most few experiences (all with relevant status)
- UA put me on a nonstop flight so I could connect to a 3rd onward flight without a forced overnight
- NZ were going to put me on a indirect routing (I was on a nonstop) with QF until they realised that would arrive at the destination at about the same time as the delayed NZ flight
- QF put me on NZ flight when their flight was delayed
- LH put me on AF on indirect routing (more than twice as long as original flight) so I could salvage a meeting