I've been coming here for several years now (since its previous location on Scottadale road), and find the pho quality acceptable for the most part, and love the atmosphere and service. So maybe 3 stars for pho itself and 4 stars for the service/atmosphere?
Problem is that I find the combination of the two features (pho and live music) a little dissonant.
Traditionally, pho is a breakfast meal and the broth can take all night to cook, eaten during a sliver of peaceful time you can find in the day. Pho served here is indeed that-- big broth bowls for roughly $8/$11 for regular/large bowls. Quality is a little lower than other pho but is otherwise as traditional as any pho place you'd find in the US.
The type of music/karaoke that's done at Pho Cao, on the other hand, is the opposite of that (despite some good acoustic musicians here!). I think it's awesome that the venue is trying to trendset the two, but honestly the pho quality doesn't support it. The servers seem to work pretty hard but it's just not the same pho quality because of the interference with bar/drink duties on top of food.
If at all, I'd be willing to pay more for higher quality pho (and served differently than a traditional large bowl style) as that would jive better.