Very good Job IMO. The HDR looks great and you certainly captured all the Dynamic Range available.
As for the stiching I think it looks excellent!! The verticals even towards the edges are near perfect, and had you used an ultra wide angle that would not be the case IMO. The destortion factor of my Sigma 10-20mm sux for Strait lines in buildings and stuff. Using a panoramic method works really good for this type of shot and it shows
Over all I think you did a very good job processing and there are several good tips I read in this thread for your next effort
Keep up the good work!!
Best,
Jay