I been an Inroads/Microstation user for last 4 years. For the last few months I been working fulltime on Civil 3D pretty much trying to do the same thing that I did using Inroads.
Following are my comments:
Pros:
1. Civil 3D is very very DYNAMIC compared to Inroads. No question about that
2. Corridor Modelling is little bit simpler in Civil 3D compared to Inroads
3. It will suit well with the BIM line up of Autodesk especially Navisworks, Eventhough they don't talk much now, but I am sure in the future they will
Cons
1. It seems that Civil 3D is very 'hi fi" technology running on an older platform. For every command it looks like it throws everthing in to the memory. Every time C3D has new releases, we have to upgrade our machines. On contrary Microstation runs on a much sophiscated platform, which requires less memory regardless of relaeses until XM.
2. I am having a very very hard time dealing with reference files compared to Microstation. Being a Design Engineer, dealing with reference files is like 1/4th of my job.
3. In Civil 3D all the aspects of Corrdior Modeling (Alignments, Profiles, Assembly, etc. ) is stored in one dwg file (well I guess that whats makes it dynamic). We have 64 bit high end machines, still Civil 3D crashes all the time. As the corridor becomes bigger, it gets worse. (Right now I am working on a 10 mile complex highway project)
4. I am not sure how this will work with multiple engineers working on the project. I hope this is where the Vault comes in to picture, which we haven't used it yet.
5. Finally Assemblies. Boy I have to brush up my VBA skills to do some assemblies that are out of the box. Setting the Target Parameter for a custom sub assembly requires huge programming skills. These things can be done so simply without any programming in Inroads XM
Conclusion
Am I biased towards Inroads/Microstation becasue of my history? You guys decide!!!!!!!!!!