The problem I have with Tom is he keeps making the same album over and over.
WHAT?!?! Compare "The Heart of Saturday Night" with "Small Change" with "Swordfishtrombone" with "Mule Variations" or "Bone Machine" or more recently, "Blood Money". There have been some phases he's gone through where several albums may have similarities, but if you look at the broader picture of his entire career he has evolved and changed. Waits is an absolutely brilliant songwriter and performer...entirely unique. I could not disagree more with the opinion that all his work sounds the same.
I would never have drawn any similarities between him and Springsteen either. Waits uses a different vocabulary both verbal and musical, speaks of different worlds, and is far more unique and creative than Springsteen (IMHO of course).
Rain Dogs is a great album. I think that's one of the early albums when he first started collaborating with his wife, Kathleen Brennan (I think he went over to Island Records at that time). If you like Rain Dogs and have not heard Swordfishtrombone definitely check that one out as well. There's also a collective CD of his "Island Years" that you may enjoy.