We are a survey-only shop, and C3D is definitely a mixed-blessing. However, we seem to be one of the few companies that really used most of the features of Land Desktop, digging deep into the product. So we've really liked the improvements C3D makes in many regards. However, the benefits so far are largely cancelled by the issues and problems. That keeps changing, though, as we get more familiar with the program, and as Autodesk continues to make improvements.
With the 2007 SP3 version of the program, there are the occasional items that we could do faster in Land Desktop with Map. But there are more items that are faster and easier in Civil-3D. We're now reaching the point where, in general, it doesn't take us any longer to do things in Civil-3D, and some things are much faster than in Land Desktop. All in all, despite the problems, I think we're happier on C3D than we were on Land Desktop. And as the product continues to improve, we should lose less and less time to the problems. It will still be a while before we completely recoup the costs of the transition, but that should happen relatively soon, after which everything else is profit. At least, that's the plan...
I can't say it's a good idea for all surveying companies to switch to C3D, but I think it's working for us. We're on the leading edge of technology, and getting better with it all the time. That should give us a distinct advantage in the coming years, as more and more people begin to realize the benefits of model-driven CAD, and begins to dominate the industry. But it can be painful being on the bleeding edge of technology, and it's definitely not for everyone. If you think you're up for the task, though, I think there's significant reward to be had...
As for training... After seeing several firms attempt the transition, and after going through it ourselves, I'd say beware of any instruction that uses a "magic disk". This is a CD of carefully-prepared, canned "course materials" that the instructor brings to class, containing all the projects and files you will use during your class. From what I've seen, most people who get this type of training are completely lost as soon as the instructor leaves, and they try to work with their normal, every-day data. I highly recommend that you ask some questions about the training, and if it involves a disk of "course materials", search elsewhere for someone who will offer you custom training on your own real-world data. If the trainer isn't comfortable enough with Civil-3D to teach a class using the data you work with every day, then you shouldn't be hiring that person for training.