I've eaten pho in Stockton and Sacramento, CA; Toledo, OH; and in the Kingsport/Bristol/Johnson City area of northeastern Tennessee. I would love to make my own sometime but I've heard horror stories of failed attempts. I saw a failed attempt once and it was not pretty. The guy got the recipe from a Hmong friend and I'm not sure what the problem was but it might have been a translation error. The best thing you can ever do to feed your Pho cravings is become good friends with people from southeastern Asia and then pray that they'll invite you over to their house for pho sometime.
When I was in Sacramento I ate at a variety of Pho joints before settling on Pho King 2 (6830 Stockton Blvd.) as my favorite. They had an avocado shake that was out of this world. My decision was probably partially based on the name of the place but they had a constant stream of Asian clientele which in my opinion is what you want to see from any asian restaurant.
From eating in a variety of pho places I've learned a lot.
1. Generally the best pho places will have southeast Asians eating there.
2. The best pho places will focus mainly on pho in their menu and advertising - you should never go to a place that specializes in Asian fusion or sushi and order pho.
3. The best pho is cheap - I generally don't expect to pay more than $7.00 unless I get extra beef balls. In Cambodia it costs 50 cents and while I've never had the pleasure I'm sure it's excellent. (extras and variations, like seafood, can cause this price to vary)
4. The best places will offer multiple sizes and cuts of meat on their menu - 1 of the 2 isn't bad but if the menu just lists "Pho" as a single item I wouldn't get my hopes too high.
3. all pho should come with sides of bean sprouts, Thai basil, cilantro, hot sauce (either as an oily hot pepper paste, chili garlic, or Sriracha - preferably all three), hoisin/oyster/or plum sauce, a lime wedge, and whole or sliced hot peppers. You are perfectly justified in asking for these if they are not brought out to you at your meal
4. You might just no be able to find good pho in your area. - Toledo once had Saigon Bistro, a Vietnamese pho joint that featured all of the things you want from a pho place. Unfortunately nobody ate there and it had to close down. Now I go to Wei Wei (1202 North Reynolds Road, Toledo). It's decent and as far as I can tell it's the best I'm going to get within 40 miles.
Random Fact: Vietnamese, Thai, Laos, and Hmong all call it "Pho"; Cambodians insist on referring to it as "k'tieu" and they are all distinct