I used them for a few years. Never anything particularly interesting in the results which is a good thing of course. I know the tests can alert you to problems before they become big problems, but in the end it was too much hassle for me. Modern ICE engine oil is fantastic and the question of "which oil" is more for entertainment than practicality. Change it regularly and oil analysis is kind of a waste of time, imho.
I think the service is probably a lot more useful for fleet or industrial applications trying to optimize maintenance intervals and avoid downtime. Or perhaps individuals who really push their equipment (tuners, racers, hot-rodders). For me, cars usually last a long time anyway so I saw little marginal value.
That being said I am curious as to how well this "lifetime fluid" is doing at 67K