I really think that it depends on your needs.
I have one on my Lang 84 and like it. I use it to keep things warm and don't cook in it.
You could porbably get away cheaper buy passing on the warmer and buying a Cambro. Here again it depends on your needs as the Cambro will take up space in the car if you plan to tow the smoker anywhere.
My Lang 60 doesn't have a warmer so I use the cambro with it and get great results.
Think this out carefully before spending your hard earned cash.
Lang 84 Deluxe Warmer with Chargrill
XL - BGE
Med. BGE ( Bought it for my son Vincenzo)
Kenmore Elite Gasser
Camp Chef Outdoor Stove
Blackstone Pizza Oven
Blackstone 36" Griddle