Phuong Nam Shuttle Service

I have taken these shuttles times since. It’s very simple just buy the ticket and they will pickup at any hotel. Also, you can call the shuttle directly to reserve your ticket and pay on the shuttle.

You posted on the Da Lat forum but asking about shuttle from VT to Tan Son Nhat. 

As far as Vung Tau shuttles go, I've been using them on every-other-month basis but never with a large bus such as Phuong Nam so I cannot tell you whether they would pick you up at your hotel.  The 9-seater vans ALWAYS pick you up and drop you off at any address you give them.

I've tried a few different companies but always came back to Huy Hoang.  Their vans are the newest amongst all the 9-seater ones, sparkling clean, and with strong Wifi.  Ticket is 160K and you pay the driver either at the rest stop halfway to Saigon or just before leaving the city (not when you board).  You must call their office to reserve A seat (not THE seat) , and make sure to be ready way ahead of time.  They WILL call you 30 minutes ahead and pick you up 15 minutes earlier than the time you indicate.

I wouldn't reserve online.  When you reserve directly, they will call you if there's any change and will accommodate your needs, but when you use a third party such as online booking, the shuttle company may not take responsible if you're not notified.