Well I have mixed feelings on this. I'm happy that Bendis is finally leaving the Superman books as he's done a lot I haven't been pleased with as a fan. However, it also means that Bendis will have left his mark on Superman because I doubt the next writer will sweep Bendis' mistakes like Rogol Zaar, aging up Jon and revealing Superman's secret identity under the rug. I probably won't pick up the Super books even after Bendis is gone as it's still an undesirable status quo for me as a fan. Hopefully somewhere down the line these changes get reversed.
I figured Bendis would want to stay on Young Justice and the Legion which means his monopoly on the Superboys will be continuing. Even with their poor sales, DC may let Bendis keep these books in his Wonder Comics corner which would be a shame not to get fresh blood to rejuvenate these titles.