If you want to learn and challenge yourself, use arduino, its programmed in c++ but you can use SOAPBOX SNAP to do ladder, and there are many IDE's that use blocks and all sort of methods to programm it.
Plus the hardware is dirt cheap. you can get a pro mini for not even 5$ and it has 6 analog inputs, 14 discrete pins than can be either inputs or outputs and 6 of those than you can output PWM, so kinda like analog.
You can add wifi, bluetooth, ethernet, GSM, GPS... lots of fun. But you will need a soldering iron, and if thats not your thing then I would say a Click PLC.