Sorry to be a "Debbie Downer" here, but I'm going to be a little more blunt: I absolutely HATE the update. Like Apple Maps and "The New Coke," they took a terrific product and broke it.
Others have mentioned font size, being unable to "turn off" features that take up screen real estate, and I want to second all of that. I want to add that the new UI is problematic not just because it "doesn't look good," but the choice of colors makes it just plain hard to read. "Medium Grey" letters over a "slightly less medium grey" background? Or, my favorite, white lettering over a light grey background? And, why do you choose those hard-to-differentiate foreground/background colors for your smallest fonts? (e.g., look at the dates at the bottom of a "Task Details" page).
I hope that the developers put together a way to revert to the previous version. I guess I'm now officially a former ToodleDo fanboy.