I am presently a part-time driver with this company. The pay is decent for supplemental income, though it means sacrificing time with my significant other as I drive through the evenings. Overall, if you prefer less social interaction, a job as a driver is certainly not a bad thing, though dealing with rush hour traffic is certainly stressful. You're also responsible for taking the vehicle in for maintenance when required, but you do get paid for your time.
The only real problem I have faced concerns communication for non-routine matters of urgency. It is difficult to reach anyone with the company who can assist you in a timely manner, and it's also difficult to know who to contact for what purpose. Someone I have needed to reach two or three times during the past few weeks has a direct line listed that is not available, and will not pick up his cell. His voicemail has been full for some time. At the beginning, they send you a lot of paperwork that doesn't necessarily clarify any of this or the chain of command in these cases. Mostly I can turn to my immediate supervisor, but this is not always the case.