If you take the time to learn how to properly set up the dist and get the vac advance lined out, you will never go back. Not talking about race cars that need locked out distributors. I have done a couple for my friends MP dist(old style) with the FBO plate and getting the canister right and they are much more responsive and actually picked up 1-2 mpg. On a street car, Vacumn advance is your friend.
I'm currently using a mechanical-only distributor, but am interested in whether I can modify an older MP electronic distributor to work properly with vacuum advance. The problems I've had in the past was due to too much advance at cruise RPM and/or the rotor phasing causing misfires when the advance plate rotated.
I found something on FABO, IIRC, that a member there who I also see on occasion here ("Mattax"?) posted regarding modifying & tuning OEM-style electronic & single-point distributors w/ vacuum advance units. It has some of the same ideas that I had to try, as well as some testing results. If I find the link, I'll add it here.
