I haven't used the 5" colour neg, but it interests me greatly. Maybe I will get some and play. I have a project that really calls for maskless capture, and so far all I have is the maskless c41 'digibase' stuff which, frankly is not really only soso. And anyway they told me they couldn't supply digibase larger than 120.
Anyway yes I use the 5" aerial panatomic-x and it is very sweet. Been meaning to check it out in rodinal but haven't yet.