I like the 20/20 monitor.  If you go that route and are truly trying to improve your planter performance and grow more bushels it may lead you to fixing things in other parts of your cropping system.  The increased amount of data and information can show you other problems in your system that you will want to fix.  Example - You may decide you need to improve your ability to control downforce or something in your tillage system may need to be upgraded or changed.