You write that you have a Planet Bike eco rack, fine around town. Perhaps stick with it? If you ride credit card, i.e. fairly light, your rear rack will be used sporadically to carry light loads. It should be fine.
If you still want to up your game, I can only say that I have several Tubus Cargo (classic) and am very satisfied. Some complain about rust -- never a real problem but yes, you'll eventually see surface rust and will shop for nail polish to touch-up spots where the paint has been abraded, if you feel that these reflect poorly on you
. You may want to splurge for the stainless steel version if this really bothers you.