I think it depends on your definition of what is real. If real means within the realm of the five senses, then they are as real as non dream state. You can see, feel, hear, smell and taste in a dream. In fact reality too is all perceived "in the mind" just as a dream is. Think about this...if you therefore take away your 5 senses as your metric of reality, by what other definition does reality exist? For others it might, but not for you since you cannot perceive it. So I am moving in the direction of saying the dream realm is "real". I always thought the difference was that dreams are not persistant, but some experts in LDs claim to have persistant realms they visit. So reality seems to be somewhat hard to define.