Can I really appreciate the difference between slave and free in American history?

I was listening to Annette Gordon Reed on television as she talked about Sally Hemings, her Hemings relatives and Thomas Jefferson. Gordon Reed was musing about Hemings decision to return to the United States with Jefferson after they had lived in France together for some time. In France, Hemings was free, while she would return to being a slave if and when she returned to the United States. Apparently Jefferson promised that she would be well treated on return to Monticello and that her children would be manumitted at age 21. Hemings did return to Virginia and we lose sight of her after her return.

Gordon Reed said that a Hemings woman slave in Jefferson's Monticello probably would have worked in the house, not in the field. Presumably she would have been reasonably well treated by Jefferson and those around him. Still, as any modern American, it seems very strange to me that someone would choose slavery rather than remain free. Yet, the real choice was for the young woman to remain alone in France and try to make her own way there, or to return to a life in Virginia that she knew and knew she could survive. I have also wondered whether a young woman living with Jefferson might not have felt considerable affection for him -- he was so gifted a man, so widely respected by others.

Then it occurred to me to think about the life of a free married woman in the United States in the 18th century. Of course, she would not have been able to vote. Any property held by the couple would be controlled (legally) by the husband. If she was a farmers wife, chances are she would work both in the field and in the house. Her life would probably have been harder than that of Sally Hemings' life in Monticello. It is not clear that the children of a free black woman of Hemings' generation would have been better than that of her children raised in the Jefferson household and freed at 21.

I also happened to listen to Colum McCann discuss Frederick Douglas' trip to Ireland in 1845. Douglas, a former slave who became a great abolitionist, was invited by members of the Anglo-Irish Protestant Ascendancy. As their guest, he traveled around Ireland speaking to large crowds in various cities.

McCann points out that Douglas faced a dilemma. 1845 was the beginning of the Irish potato famine. The Catholic underclass was desperately poor. Many would stave to death in the next few years, many would die on plague ships trying to escape from the hunger, and many would immigrate into a new world for which they were ill prepared. The lives of the Irish Catholic poor were worse than the lives of the slaves in the American South. Douglas was faced by the choice for speaking for the desperate Irish and offending his hosts, or continuing to speak against slavery. He chose the latter.

So, perhaps Sally Hemings was right to choose slavery for her own welfare and that of her children, and perhaps the average slave in the American south was better off than the average free Irish Catholic in the late 1840s.