I've been really impressed with the development of 2Do for Mac and iOS. While I don't use it on a daily basis, It has a lot of clever interactions and it's clear the developers use it themselves. It may be one of the best new task managers on the market.
Now you can get either version for 30% off the regular price.
2Do for Mac | $35 (on Sale)
2Do for iOS | $10 (on Sale)