No experience with the Grand Design or the Jayco. But, before settling, take a look at the Keystone Outback 298RE.
We've had ours for over 3 years now. The basic floor plan has not changed in 5 years now. No problems at all with it at all, except for stupid things I've done myself (like turning on the water heater with no water in it, and forgetting to remove caned cola from the fridge and they exploded when temperatures got to -20 below zero (F). Tows wonderful, perfect for 2 people, Queen bed, with slide out closet, rear living room with opposing slides and outside camp stove and sink.
Ours came with a free standing table and chairs. We removed them and the 2 rocker chairs and replaced everything on that slide with a household style full 3 seater recliner couch. I put wheels on it, can turn it facing the rear window when the slides are out.
Also, everything is accessible when the slides are pulled in. We often use the camper with all slides in. Especially in the winter to help reduce the space to heat when we winter camp. We put a second television in the bed room, so don't need to depend on the one in the living room when slides are in.
We love this camper. If we ever lost it, I'd get another one just like it.
Your model has a larger slide which includes the kitchen, mine does not. Yours has a King bed in the slide, ours has the closet in the slide with a Queen bed walk around. Ours has a corner cabinet right by the door, yours has a cabinet by the refrigerator. Some differences, but still worth your time to take a look at the 298RE.