I have a 2013 Northstar Igloo 9.5 which has been in the truck for about 18,000 miles and 100+ days of camping. I've had no problems at all with the Heki over the bed. I have the propane powered Dometic fridge and have had zero problems there too.
As for leveling, I read about some folks struggles and worries getting it just so. My ford truck has a level gauge built into the digital dash and we find that we can park every time no more than 1 degree off level just by seat of the pants. That works fine for us and takes no more effort that going backwards and forwards a bit and feeling the level of the truck on variations under the wheels. I verify it by checking the level gauge.
If I were to be ordering mine today I would have them leave off the ladder and use the Heki for roof access. As it is I will probably remove the ladder and use the space to secure my grill.
Enjoy your Northstar, we certainly love ours.
