Two questions/observations regarding the auto resolve option for battles.

1) Mana usage - When I've selected the auto resolve option and checked the log, it will say that my sovereign has used spells but doesn't get charged for mana for the spells they've used.  If I fight out the battles and use spells, my sovereign consumes mana that can take time to regenerate.  So it seems like not only can I save time, but I can somewhat exploit the system using auto resolve and not get charged mana.

Which leads me to #2

2) What's your experience been with letting the computer auto-resolve battles?  In the early stages it appears to be doing okay so far.  I did lose an adventurer NPC once though cause he took all the damage.  I had summoned units so I would have expected them to take the brunt (they are cannon fodder after all).

The reason I ask is that I've played games in the past where if you chose auto-resolve you were probably going to lose much more than you would by playing out the battles.  While I don't mind it, the tactical battles do get repetitive afterwhile.  I'd prefer not to have to fight against the trivial stuff.  However if the trend is that auto resolve tends to inflict more casualties then I'll do the tactical battles.