Not to be a contrarian, but I stay at PH Saigon a lot. I use an ABTC card which always gets me through immigration in 3 minutes max and then spend $6 on Grab or a Vinasun taxi to get to the PH (or sometimes walk after a long flight if I get in early morning and it's not too hot.)

Don't mind spending money for good service, but the PH fast track/car service is such a rip off, I'd feel like a complete rube using it.

Lovely hotel by the way. Great staff and great service.