listing it as I haven't done enough due diligence to validate what I have done...which was basically copy what someone boardmailed me.
Initially, in the early years, I was evaluating each note. That got too tedious after about $500, so I switched to buying 3 year C notes, no other filter. I figured if the averages held up, I was good. About a year ago, someone boardmailed me with a filter suggestion, and I was too lazy to evaluate, but I did switch. A very small portion of my notes were purchased under that criteria. The magnanimous board mailer told me he had done the evaluation of all of the notes and his returns seemed to indicate they were working. I don't have enough info on my returns to confirm they have worked for me, but he was pretty sure about them.
You can download all of the historical data - defaults, location, reason for borrowing, etc from their website. It is very transparent. If I was younger, I would definitely spend the time and do it. If I ever were considering moving big money, I would definitely do it.