Get the Grill Dome because of the stainless hardware. The Primo Oval XL is too massive and the Oval JR is too small for entertaining. The BGE offers no significant advantages over these 2 competitors other than being more widely available.
The top vent on the Primo is rather primitive compared to the competition, but the oval shape is a more efficient use of grill space.
What this misses is the fact that both the Oval XL and Junior have a firebox divider at the midpoint of the firebox which allows one to cook truly indirect, or directly over half of the firebox for short cooks, or remove the divider and put up to about 20lbs of lump in the entire firebox space. I have done too many 14-16 hour cooks on half a firebox single load of lump to remember. I would estimate 95% minimum of the cooks I do on the Oval XL use just one side of the firebox which ends up saving a lot of lump. The Jr is a very good unit which offers much more available grill space than a similar BGE or other. I have had an Oval XL for 5-years and never had an issue with a hinge, vent, etc and the grill grates are still going strong and I have used the shite out of the unit. It holds temp constant very easily with a "primitive" vent or not, and if you use a computer controlled forced air unit on any ceramic for low and slow they are all better for it.
I would buy the biggest unit you can reasonably afford, and I much prefer my cooker to the neighbor's BGE XL. I have no financial interest in any of the grills, just calling it from personal experience. Whatever you get it is better off set in a table, not one of the nests, with high quality stable wheels on the table b/c all of them can be a bitch to move and you don't want a shattering experience.