I very much enjoyed the run last year. I actually travel up from Berkshire for the run, because my wife's family are from Chester. The course is fairly flat, but It is a bit of a climb to Eccleston on the way out and the way back. Take a look at http://www.mapmyrun.com/run/united-kingdom/chester/418939 and click on show elevation to get the profile.
Ran last year and will run again this year. Had a great time. This was the flattest half I've ever run and people were still complaining about the subways being hillier than they expected??? For me, the final few hundred metres inside the track and field stadium were some of the longest I've ever run. When you enter the stadium you feel like you're at the finish...but you're not, there is a small matter of circling the track.