We previously purchased a queen size ghost bed about a year ago to replace our badly sagging queen spring mattress.
We were very happy with the queen size Ghostbed, but did have issues with movement. I weigh around 230, and my wife is around 140. My wife would complain that she felt she was getting pulled towards me due to my weight on the bed. As much as we loved the queen Ghostbed, it's size did not meet our needs.
So this time we upgraded to a King size Ghostbed (moved the queen Ghostbed to guest room). The issues with movement or my wife getting pulled towards me due to my size have completely gone away. She has had back issues in the past (reason we went with Ghostbed to begin with), and would stack pillows around her for support. That has ended, and she has told me several times how great the bed feels now. I have loved the Ghostbeds (queen & king) since we got them. They feel great, are super comfortable, and offer great support (even for my size). We have two small daughters, and every so often they share our bed. Used to have crowding issues, but not anymore. They also love the queen Ghostbed in the guest room for naps. Super cozy is what they say, and they are right.
In addition to the mattresses, we ordered a king size boxspring/foundation from Ghostbed and received three free Ghostpillows.
The boxspring/foundation is made of solid wood, and super sturdy; it's also pretty easy to put together (kind of heavy so dual lift recommended).
The pillows are awesome. We have gone through tons of regular pillows of all types. These are the first pillows where we haven't had to use more than one to sleep on. They become an extension of the Ghostbed, and the pillows and the bed both absorb you into the bed/pillow. I also had issues with having to turn pillows over when they would get hot. Not with the Ghostpillow. The cooling layer on top works great. We did notice a nice lavender/basil like scent from the pillows when you squeezed or lay on them. Not an issue for us (we liked the scent), but somebody else may have an issue with that.
Conclusion: If you and/or your spouse are a bit heavy I really recommend the king bed for the space. If that isn't an issue, the queen size is great for an average size couple. The Ghostbed boxspring/foundation is solid compared to the spring type boxsprings. The pillows are also highly recommended, especially if you buying a Ghostbed.