You still get the EXP/Limit Points and Allied Notes from Campaign as well as the reward from the Campaign Op.
If you accept this mission and join a Campaign Battle but leave before it has finished, you will still receive experience/limit points but you will receive NO Allied Notes upon return to your nation.
I put Allied Tags on mid-battle and took them off about 10 seconds later. I got EXP as well as Allied Notes from Windurst. - Xonal, Asura 5/27/09
A notice saying you have completed the mission will appear in the message window with Experience and Allied Notes upon satisfactory completion of the objectives.
Beastman Confederate forces are now planning full-scale seiges on federal strongholds within Windurst territory. Join the battle along the Sarutabaruta and Aragoneu fronts and assist our mercenaries of the Cobra Unit in defending these key strategic points.