The lower cost of replacement parts plus the fact that you can use the more commonly available 12 pole tach is a big plus.
Not sure how others feel but when ever I had to trouble-shoot the Prestolite system, I would have to deal with a big ball of spaghetti wires between the coil mounting plate and the block. Not impossible to do but the CDM system is much more modular and no wiring mess to deal with.
One thing that I wanted to say about the CDM system ( any other ThunderBolt system that uses the Regulator/Rectifier), was that the bullet connectors on the Yellow battery charging wires from the stator don't seem to be that great. I've seen quite a few of these connectors that have gotten so hot that it has melted or discolored the clear plastic cover on the connectors. To prevent this from happening, I just cut the connectors off and used eyelet type connectors and a stainless steel four position terminal strip that uses screws to secure the wires. This has worked fine for me.
NOTE: Once you convert over to the CDM ignition, you can use the NGK BUHW plugs which have a larger spark gap. Supposedly that's better for ignition. I didn't notice much difference but just wanted to throw that in.