I've got a friend who has Big Green Egg. The main selling point of those or the clones is the shape and the ceramic construction allow for a very high temp when desired for searing, like >700°. I will say be cooks some mighty fine steaks on that thing. May not be as good for smoking though, although he did a Boston butt on it that was awesome.
I’ve had a BGE for about 12.5 years. They smoke just fine and there is an endless amount of after market support. There are more grates, plates, racks, stones and gadgets than you can shake a stick at. It is an awesome 1 grill solution. Will do it all. Well. But as a lot of people here have noticed there may be quicker easier ways to smoke using pellet grills. Not sure the food is any better, but it takes less effort.