Only done the South but can thoroughly recommend it as a destination. Not sure you can really plan to see the Aurora, just hope that a good show coincides with a clear sky! Car hire was expensive (£800 for 10 days inc fuel), accommodation was reasonable (pricewise, comfort and warmth was excellent everywhere we stayed), food was edible (harder for veggies but not impossible) but a bit pricey, drink was not cheap (buy at duty free on entry). Highlights for me included (but weren't restricted to) the cliffs and beaches at Vik, the ice lagoon and beach, assorted waterfalls and the horses + reindeer.