I am not a great chef, but I love good food... so this is the perfect cooker for me..
First, its BIG, so you can cook a LOT of food, or cook a big roast.
Its claim to fame is the temp sensor.  It works wonderfully... u set it to the desired wellness, and just turn it on... and it does an amazing job.  The only tricky part is, if you put steaks of a different thicknesses in, they will all cook different, and the one with the probe is the one that determines wellness.  So try to have them all the same size to assure same wellness.  The parts are easy to clean, drop em dish washer, and wipe out the unit.  The electronics are simple to understand....
I have not tried a roast yet, but that is next... 
its hard to find a flaw with this cooker, Just love it...great for the set n forget crowd....
Ninja makes great products and reasonable prices, kudos to their design team