If going to SD, don't fly into PC
A delayed followup, but just wanted to share from experience from a trip in Feb..
As an english-speaking visitor with very poor spanish-speaking skills that hadn't been dusted off in 15years, I arrived with my fiance at the PC airport on our first trip to the DR. After obtaining our luggage, we were informed by 'folks' in the cab area that waiting for a Caribe Tours bus was not the right choice: many hours until one was available, and would be best taking a cab to the Bavaro Express hub. So with nothing else to rely on, we did just that. I'm guessing it was about a 20min cab ride (can't recall the price).
When we got to the 'bus depot', it was a culture shock. It appeared that this was transportation not utilized by tourists-- and definitely not unless you spoke fluent spanish. It was busy, crowded, and had no resemblence of any bus station I've ever seen. There was no formal ticket booth, rather people standing there taking cash and handing out 'tickets'. We only had US dollar but only DR Peso was accepted.. and no way to exchange. If it wasn't for the generousity of a local seeing that we were completely out of our element, we wouldn't have understood how the system worked and been lucky if we even got on the right bus.
The ride to SD took hours, and when we finally arrived at the 'bus depot' in SD, the chaos started all over again. Understood through my broken spanish skills it was the bus station, but it looked nothing like what I know them to be. While again we were lucky to rely on the generousity of a kind local (saw no other options), we spent hours with our very large backpacks getting on and off guaguas trying to get to our hotel. While we eventually got to our hotel and learned after about a day how to enjoy (and LOVE) being immersed in a such a foreign environment, never would I recommend first-timers doing what we did to get to SD. While later in SD we did visit the Caribe Tours bus hub, I would say that it appeared much more like a real bus station and would chose it over Bavaro Express anyday. To us: the cost savings of taking a bus didn't offset the time and hassle to get there. Without a doubt (especially if your first time in the DR and don't speak Spanish): if you want to go to SD, fly into SD.