Personally it's been like a 8:2 easy to hard transition ratio.
Pirox takes a bit of time to set up a proper combat profile, and if you're using it to grind a toon from 10-85 using PvP you either have to initially make the profile suit your current level and abilities and then constantly edit it as you level and abilities become available, or just go with what you'll be using at 85 and leave yourself gimped until then. Whereas HBs default CCs will automatically detect your spellbook and your spec then create it's own combat routine, I find that so much easier and a lot less bot like than wasting globals because the abilities you have set on timers weren't in your spellbook yet. Also HB seems to auto detect what toon you're using and brings up your previous setting from that specific toon, whereas with Pirox you need to load profiles by hand, which I would sometimes forget to click load after picking my toons name from my drop down list and when I'd click run it would completely overwrite my settings, so HB pretty much saves me from myself in that right.
I found all the plugins and different aspects of the bot to be a little intimidating at first, I also wasn't familiar with the prefixes people would put at the beginning of their profiles, for some reason [PB] kept making me think I had to load it into the Party Bot part of HB instead of ProfessionBuddy. Once things start to click and you have what you need to get started it's practically effortless. For the most part this bot as a pretty low learning curve and even first time botters shouldn't take more than an hour or two to get at least a basic grasp on how to work it, especially when the mods/developers put together entire packs with everything you would need, free of charge. I also had some problems but they were my own fault because I didn't bother to read certain things, like Allrounder, I downloaded the plugin using the authors SVN but when I tried to run it I would get an error, I couldn't for the life of me get it to work until I actually read what the Bug Submitter was telling me the error was, now it runs like a dream.
I've played WoW for going on 5 years now, botted for going on 4, I went from Glider, to a couple underdeveloped bots that were mostly for just gathering, to Pirox, and now I am here. So far HB has been the one that I have been the happiest with, although I loved Glider, if they were still around and I had to choose between the two I would most likely choose HB. I've used Pirox for almost 2 years now and I would never go back to it full time, even though Pirox has a huge base with a lot of people who submit profiles for pretty much everything and anything you could think of, with more that were coming out every day. I believe HB will be able to do everything that Pirox could do and more, given the proper time and the right people working with it.
Certain parts still confuse me, I'm interested in creating my own ProfessionBuddy profile to prospect ore, buy JC settings, make rings/necklaces/carnelian spikes, and then DE them but it'll take some practice I guess.