First of all, sleeping with your dog you can enchance your bond between you two (or how many you have). And if you spend most of the day not together it is great way to compensate your time spent at work accepting your dog to sleep with you. It is proven that sleeping with your dog you are more relaxed and sleep better.
Close relationship with your dog can improve your health or even improve survival rates after life threatening surgery.
Talking with dog can decrease blood pressure.
Lets not forget about cons.
Fist bad thing can happen is infections (but this is more a lack of hygiene not beause of sleeping together), sleep deprivation (scientists noticed that it lasts longer trying to sleep and moreover people got up more tired if they slept with their dogs, but again it depends on many factors, for example how good your dog is trained to behave) and behavioural issues in your dog (depends on breed, training, situation.. but if your dog is very bossy it can make changes in your dogs behaviour).
As you see, scientists have not confirmed that you can't, it does not hurt or change something into bad way. But what I noticed, that my westies are much more enthusiastic and happy to welcome me in the morning when we sleep in our own beds. They are not so stubborn or bossy.
Moreover I feel better if we so not sleep together: my bed is big, but you know westies, they need to sleep close as they can, so I am afraid to kick or move not to wake them up. And of course, main reason I ask my girls to sleep in their beds is my nose, sneezing and some kind of allergy. As you know, I am tailor and there is plenty options for dusts to get into my nose, so I try to reduce these options so I could continue sewing withour big distractions.
Conclusion - know your own best way ;)