I personally love taking the bus in St Martin/St Maarten. However, you have to be on island time and not in a hurry. On my most recent visit, I was staying in Philipsburg and took the "public bus" from Back Street to Maho. It was easy and inexpensive. You may get a few odd glances as they are usually used by locals and not tourists, but the driver and other passengers will be friendly and helpful. Our driver even advised us as to where best to wait for a return bus when we were ready to head back.