I did my residency at UW and rotated for 2 months at VM. (I don't know much about OHSU, but I've heard good things and Portland is great.)
Both are top notch programs with respected faculty and good facilities, but the programs are very different after that. UW's biggest weaknesses are VM's greatest strengths and vice-versa. UW and VM were historically the biggest promoters of regional anesthesia and all but invented pain management. VM has continued the tradition and remain one of the best places in the country for regional anestheisa. Unfortunately UW's regional and pain programs had weakened by the time I was there and were the biggest weaknesses of the residency program. Things had been put into place to reverse this, but I doubt they will come close to VM anytime soon.
UW's biggest strength is the high acuity of the patients and the many varied sites and hospitals one can rotate through. (i.e. I got to go to VM!) VM residents do rotate to Children's and Harborview for peds, ICU, and Trauma, but overall spend the vast majority of their residency on 2 floors of VMMC which is a pretty small community. Their patients for the most part are older and healthier (more of a private practice population), and their anesthetic management is increasingly being standardized; this makes it a model for safety and accountability, but does tie your hands a bit with management. The surgeons and surgical residents at both places are good, but VM has much quicker and much more pleasant surgeons than UW for the most part. VM's faculty are almost entirely US trained, which is unusual for most residency programs. This is not the case at UW, but many of the best attendings at UW are the Brits, Kiwis, Aussies, South Africans, and Germans that come for a year or for good.
As far as academics go, VM faculty publish probably even more than UW faculty (but they practically have their own journal with "Reg Anesth and Pain Management") and most of their publications are on regional anesthesia. UW does more bench work/basic science, but most residents don't get involved with it unless they take the research path in their last year.
As for other things, VM gets free parking, free food, and has better hours. The residents probably are happier, are well-trained, and they get good jobs. UW has very few perks, but you will be comfortable with any zebras handed to you in the future and are desired in private practice or fellowship. Overall, I'm glad I went to UW of the two, but I would have liked VM too.