I've been to Little Saigon many times and I find that they are always busy, even if I visit during "off peak" hours. The food is tasty enough that I don't mind the 5-15 minute wait for a table.
The deep-fried spring rolls are delicious and a generous size as well. I think they fry them to order (as I've never had them in any state other than piping hot and crispy). I find their pho broth to be mild-yet-flavorful and non-greasy, which is nice. I like the fresh herbs (with minimal brown spots) and non-soggy sprouts for pho- it's rare to find a place that gives consistently fresh herbs and sprouts for their pho.
The customer service is fast-paced but very friendly, I've never had a bad experience with anyone being rude. Will continue to come back when I have a craving for Vietnamese food!