Just upgraded from 2.5 to 2.6. Scheduling and logging is a big improvement, though I think it could be done better.
Especially the logging bit, it relies on the scheduler login function which is not very nice.
I would like to see an option within the module itself, so I can see when which newsletters has been sent to who.
And I would like to see an option I have seen in another application where it keeps track of the number of bounces, and you can say delete user/address after x bounces.