I judge every Pho place by their Pho Tai.
unPhogettable's pho has an incredible broth. They also don't skimp on the pho toppings (I should really learn what these toppings are called--it's the dish with the basil, sprouts, jalapenos, limes, etc). I like the atmosphere of this restaurant because you can exit to the parking lot in the front or to the Asian market area in the back which reminds me of the small malls strewn about in the semi-urban areas of Japan and Thailand.
Only issue I have with this place is the price. You have to pay $8+ per bowl while Saigon Pho in Chandler is $5-6 and has better pho and quicker service.
Pho kind of reminds me of Chipotle. The heavily frequented Chipotles tend to have the best quality food (this is anecdotal but I am a former manager of Chipotle so I'd like to think I speak from legitimate experience). I'm talking tightly rolled, good salsa and sour cream distribution, the works. They simply get more practice and it shows. The unfrequented Chipotles tend to suffer in overall food quality. This goes for Saigon and unPhogettable in the same way. unPhogettable just doesn't have as many people come through so they don't really have the pho experience down to a science (yet). Nonetheless, you'll still enjoy great food and a nice walk through the market afterwards.