Van Loi two and Pho Hien Vuong are the best in gso. they have good broths and give you lots of herbs for the broth. I tried the saigon's pho yesterday for the first time and although most other items on the menu are very good their pho is nothing special. The ingredient quality was fine but the depth and quantity of the broth was not as good as others and they skimped on the herbs.
I just discovered van loi in the last 6 months and I think the best item is their roast duck in mushroom soup. basically duck pho. I have also had the meatball, rare beef and tripe pho - amazingly delish. Saigon does better on other menu items like bun and many other rice dishes. Tthe roast pork in the van loi's deli is good to and relatively cheap but their banh mi are horrid(bad bread).
Van Loi 2 Vietnamese Restaurant (3829 High Point Rd Apt D; Phone: (336)855-5688) is my favorite. They have an extensive authentic menu. They also have a deli right beside the dining area complete with roast pig, duck, (and for the more adventurous) chicken feet - my personal favorite. Not as thrifty as those pho cafes I dearly miss in East Oakland but just as good.
I do not know of any really pho centric rest in triad. I would just go for saigon. I have never had the pho @ Saigon but in general their quality of ingredients is better that other are Viet. places. I went to Binh Minh on Market and the pho was poor. The broth had no particlar intensity or depth of flavor and some of the greens were wilted.
All other Vietnamese places I have tried have had much sadder looking ingredients than Saigon and much less pride in presentation. The place on Florida St may have more exotic ingredients though(tripe, etc). But service is subpar.
I am no pho expert but I did have what I think many would consider good pho @ a church fundraiser in HP. Check out the Banh mi in the same shopping center of the FLorida st Vietnamses place. They gave me the flyer for the fundraiser and they said one should be coming up in Sept or Oct.
Sorry for rambling but I hope this helps