I've been using the Udon Thani Immigration service since they came back to Udon, which was even before they moved into the police station complex. I have never had an problem with them, though I have learned to ask, on my last 90 day report prior to extending that I should ask if there are any changes from the previous years.
Yeah, the 100 baht thing is the only bit that keeps them from being ideal from my point of view, but having been to other immigration offices in the years before Immigration came back to Udon I realize that Udon Thani Immigration is far better than most if not all others.