They look nice but you lose so much. I don't like that you lose storage space above and below the bed, and then you lose the use of the sofa when the bed is in place. You save maybe 2' or 3' which isn't worth it IMO. The mattress will have to have a seam where it folds and many hybrid owners complain how uncomfortable the seam is. That also means it's a foam mattress and not an inner spring mattress.
Maybe there's more benefit, but all I see are the negatives. But if your spot at your house is limited and 3' can make or break you, then these models will help.