The 'advantages' of the 'modern' upper plate was to be able to use modern available Ford points and condenser. The condenser being on the upper plate also keeps it away from the exhaust manifold heat. A disadvantage is that some feel the points are harder to adjust.
Some of the earlier modern upper plates had problems. Those within the past 10 years or so are OK and I'm one that doesn't have any issues with them.
The quality of new points and condensers is not very good, its tough to find good ones. I've found about the best are from NAPA and are expensive.
But, now, original type points and 'burn-proof' condensers are readily available from the vendors. Most folks will recommend the original type.