Simple. Called em the night before to arrange pickup at 11:15am.
The guy arrived at 11am. I wasn't fully dressed, so I called the company and they told me no problem, he would wait.
I walked out to meet him at 11:15am. He was very polite and pleasant. Got me to the Metro station without driving like a maniac. Helped me with luggage, and I tipped.
Overall, I'd definitely recommend calling these guys.