Zep grill spray twice a year (spring/fall) keeps it pretty nice. The hopper doesn't get hot, but the cover/shelf to the hopper does. Don't put your beer on there. I love it for loading/unloading the grill and I didn't have to pay extra like the other models. I usually just wet wipe the shelf after a cook and it comes clean, it's holding up well in that regard. The inside looks pretty decent because I make pizza a few times a year and anything caught on the inside flakes off pretty easily and then I can just vacuum it out.
1070 vs 590 - I may have mentioned it, but the internal difference is my firepot is flush to the floor. Rain gets in the barrel and seeks the lowest point, igniter gets wet, pops the circuit. Eventually the igniter gives out and I call for a warranty replacement. So if I lived in a drier state, I'd probably be giving the 1070 5 stars.