As far as I can tell it looks like if you don't bag or mulch but want to discharge, then you are in fact stuck with the rear discharge (no side option for HRX series). I don't think that is a deal breaker for me as I would plan to bag or mulch. However, the video of the rear discharge on honda's website shows the grass shooting all over the guys feet. 1:27 at link below:

The side discharge mowers from honda look to be the HRS series which don't offer bagging options.