There's a fortnightly radio show here with a local vet behaviourist, and I remember he discussed the trampoline beds on one of his shows. He was against them - particularly for older dogs. He said because of the lack of support (particularly as it sags over time) it's very hard for a dog to get in and out of the bed, esp for dogs with joint issues. He said it's like hammocks for humans - fun for a little bit but you wouldn't want to sleep in them. So I guess they're okay for something to lay in but not a permanent bed. They are very popular here (so many people have their dogs outside here) and I know a lot of dogs who don't use them!
I cut off a piece of foam from an old foam mattress to make beds for my dogs (with the old cover on otherwise Tully picks at the foam). I've brought many, many beds over the years and the foam mattress ones are the only ones they'll use. Deska's been sleeping on his foam next to the bed for 10 years and it's still nice and firm.
Of course, in the lounge the use the giant dog bed - aka the couch!