Jaco,
You have not found a definitive answer because there isn't one. Both the Crane and Pertronix, when installed properly, will work well. There are fans of both.
One member, Jim Villers, has had 2 box failures of the Crane. The Pertronix has no box--all self contained in the distributor. Others have had some issues with the Pertronix, particularly misfiring at high RPM or trouble at idle.
The Pertronix is a quicker, cleaner and easier install, and for that reason alone is worth your first try. It is easier to remove and go back to points. It is less then $100. Pertronix and Crane both have excellent technical support and if you tell them the kind of distributor you have they'll make the recommendation for you.
I've had both and when both were working they were great. I removed the Crane after 5 years because the internal shutter wheel was always the wrong size and it eventually interfered with the wire going to the optical breaker. But for 5 years it was perfect. The Pertronix is in now, and I've been under hard acceleration past 5500 RPM and no misfire.
Those that swear by points, point out what are you going to do when the unit fails in the middle of nowhere? Well, first of all if that concerns you, once you get your electronic ignition installed and working properly, buy a spare and keep it in your car. Just the same as if you'd have spare points, rotor, condenser and cap with you. Yes a few more dollars/euros but cheap insurance if you get stuck somewhere.
There is a third option that has been mentioned before and that is an entirely new (made in Netherlands) electronic distributor. A bit expensive but it eliminates the distributor as an issue. I don't have the name handy but do a search here and you'll find it. You know after 30-40 years there is hardly a distributor that doesn't need something when you take it apart and look. Springs, bushings, weights, etc. Our own Dr. Benz here, who rebuilds them, said something to that effect recently.
Most important however is this: the idea to go to electronic ignition rarely comes on a whim. It comes to try and correct some issue which rarely is related to the points! Therefore changing the ignition system doesn't change the problem you might have and introduces another variable!
Bottom line? Ensure your car's ignition, timing, wires, coil, and most importantly, your vacuum advance and distributor etc. are all tip-top and working PERFECTLY before going to electronic. That will ensure a smooth transition.
Both points and electronic systems get "bad raps" when it is overall poor maintenance (usually related to previous owners) that creates a problem you are trying to solve.
Michael Salemi
1969 280SL
Signal Red 568G w/Black Leather (Restored)
President, International Stars Section
Mercedes-Benz Club of America
