I've had both Arrow and the Northstar,both are great fliers,it all depends what you want.The easier to fly is the Northstar.The faster is the Arrow.If you use a four stroke,make sure you have prop clearance,you may have to raise engine box,you should use a perry pump,with the gas tank on the C.G.. If you do build the Arrow,put small wing tip floats,it will make it a lot easier to take off water.I fly mine right off the grass,no wheels.Once you get used to the Northstar,you'll want the Arrow.I have a thundertiger .45 on mine,and it's wicked.My buddies who have Northstars wish they built the Arrow.Two things on setting up the Arrow,3/16 reflex on the elevons,and use 2-56 steel rods to evelons.Once you find its sweet spot,hang on.
On the Nothstar you definetly have to make it more rigid as the plastic nyrod extends from the engine box to the elev. control horn. jeffo