When I first got Sunny I told myself that I would never let her sleep on my bed and she would have her own separate bed next to mine. This lasted for several months but I noticed that I kept falling asleep on my couch at night only to wake up in the middle of the night (or even pre-dawn) and make my way to my bedroom for real sleep. I couldn't figure out what was wrong with my sleeping habits until one night I was about to fall asleep on my couch yet again and I caught myself thinking, "Ooh I'll just close my eyes a bit so I can snuggle with Sunny some more." Aha!
Because I work full days I don't have that much time with my dogs so when I'm home I want to spend as much time as possible with them. So Sunny and Rosy sleep with me on the big bed. I don't know if my sleep quality is necessarily better though since they have some unique ways of waking me up every single day (including weekends). Still, I wouldn't have it any other way!