I ran a MSD6 with points on my TR3A for many years. Had a "teething" problem a few months after initial installation, where it literally burned away the RFI suppression resistor in the cap (along with some of the cap itself), and then burned a carbon track through the coil tower. But I was able to limp home by fabricating a replacement center contact from a paper clip. Carved a non-resistor contact from the center of a flashlight battery, new cap & coil; and it ran great for many years. Module died once, but the factory sold me a 'reconditioned' replacement at a reasonable price.
But I was worried about all the spark scatter I could see with my timing light (which in retrospect may or may not have been "real"), so I eventually switched to a Crane XR3000 (and moved the MSD to another car).
The XR3000 was a royal pain to install properly, but worked reasonably well once I finally figured out that my rotor was hitting the pickup and causing problems; plus I had to modify the bracket to get things to fit right. Well, except that time the ground connection got corroded and the unit just quit working, while driving home at night in the rain. And the engine just never did seem to run quite as well with the Crane. Started great, just kind of sluggish at part throttle & mid rpm, compared to either points or the MSD. Anyway, I won't be buying another XR3000.
This time around, I'm going for a Pertronix. (Just installed it Sunday night in fact, but haven't taken a test drive yet.) When the "hot rod" motor is completed, I'll likely add a MSD box again, see what difference it makes.