OTG = ash catcher bucket, hinged cooking grates and stainless steel one-touch ash sweepers.
Performer = same as above plus kettle is mounted on a cart with a large side table, lid holder, thermometer mounted on the lid, large shelf underneath, bucket to hold a bag of charcoal, 2 briquet holders for indirect cooking, gas assist to start the charcoal lighting process & hooks on the table to hold tongs, etc.
I own a 22.5" ots, 26.75" otg and a performer. The performer is my favorite of the bunch. A little pricey but worth every penny.