Love mine but there are problems with mould on the roof, other people have had various other issues but I've had nothing but help from the iW dealer I bought mine off.
I love my one too. For me it's better then the 510 as it's much lighter inside and the ramp can be on either side, I have mine on the right as it makes far more sense when traveling a larger horse on the left.
I had a few problems with it initially but they have all been sorted quickly and efficiently!