Does Nero log any errors anywhere if the burn fails?
I was burning various CD images and they all fail with an error, but the CD reads fine, and I want to know what's up with this...

Making a compilation on my own and burning that always works, just burning images doesn't...

Is there a tool out there I can use to compare contents of the CD to the ISO and see if they are the same?

Don't know about a log for Nero, but for the latter question, you can mount the ISO via Daemon Tools -or- extract it via ISOBuster, and then use software like Beyond Compare -or- the fc command-line utility to compare the content.