IPC-D-356A Netlist vs Gerber Files

I think you may use any gerbers tools like CAM350 to do IPC netlist compare. CAM350 will support netlist compare but you have to to check other CAM tools.

I think CAM350 is paid. Thinking of using WISE Gertool for comparing.

Update: Gerbtool is having some issue. So, can't open it.

The 'Valor' tools have an issue with reading a Cadence Allegro IPC-D-356A netlist correctly because they interpret the spec differently than Cadence, the solution for a client was to output a MentorGraphics neutral-file as the netlist instead of an IPC-D-356A file

CAM350 can't find complex shorts like Valor or Gerbtool can, I don't trust it as a tool

What is a complex short?

For ODB, CAM350 is fairly priced for our designs <1500 parts.   

CAM was an easy tool to justify buying.  When I have to release a P5DS designs, from their ODB export logs: 

"you have a short.  Which nets is a secret.  Somewhere in that <1000 DRC errors you can't fix, something is touching something else.  Give us more money."

A complex short is where large pin count power/ground nets are shorted, even Valor can't pinpoint the locations

I found that the free IC design tool KLayout supports net connectivity checks and allows import of 274x artwork files

I have used it's internal macro development to write:
  a ruby script to import an ipc-d-356 netlist to add drill holes & netname text,
  a ruby script to compare the connectivity