I had the second iteration of the HRX with the "smart drive" which I always felt was moving exactly how it wanted it. I am not sure if the new "select drive" implemented on the K5 and newer models is just as good, but I am not a fan of the spin dial and handle setup, but then again I haven't tried it. This was my rational behind favoring the hydrostatic, plus I have a lot more lawn than I used to so I want something that will last. Then again, my K2 got 7 years of mowing .25 acres without a single issue. I would routinely go between mulching and bagging with mine so I ended up having a bit of an issue where the versamow chute would not open all the way but I knew it was an adjustment thing and it never really bothered me. What I did not like rear discharge. Sometimes when grass is tall and you cannot mulch you just need to move it out from under a deck. With just under 1 acre now, I do not want to be bagging and would rather have options for leaving the clippings behind. I have never cut with the personal pace system but I have used it on a demo model in the store. Not a huge fan but I could learn to love it.
A coworker of mine told me the other day that he has TWO walk behind mowers that run that he is willing to give me. One is a Toro that is self propelled and the other may be a Honda. He said the Toro might need a cable of some sort and the Honda some new wheels. I am very leery of used equipment and I have not seen or know what they are so I continue on my journey of finding the "perfect" walk behind mower for me. I will throw in that I may bag from time to time for purposes of composting, but I have not decided on that for sure. Regardless it shouldn't weigh heavily on my decision as side discharge and mulching are more important.
I saw your other post; it sounds like the Toro 20382 is the perfect mower for you so long as it doesn't have the same tendencies as the Honda to lift when the bag gets full. I, thankfully, do not have any hills or steep banks to mow so this would not be an issue for me.
