I use mine on my WD every day. I use 1 profile for rifting, another for bounties, and another for leveling new toons through quests (each profile is a separate act). To me, it was fairly simple to set up. There's plenty of help here, lots of useful posts, just take the time to read them. A lot of the questions you may have (How do I make it do X,Y,Z) will be answered in different threads. I tried a trial access, and I was sold and now have a lifetime membership. Well worth it.
It's not "super complicated" at all. Most of it comes already set up for what you're looking for, basic xp, bounties, and storing legendaries (you can tell it to keep legendaries unidentified if you wish, I do, so I don't get unanswered "grats" from my clanmates when I'm not at my desk to say thanks).
Posts about it not working properly are usually operator error. There are frequent updates to Demonbuddy and the associated plugins, which is a good thing. You want a program that is always updated and fresh. You said you've used it for 2 games, so you know Blizz and others are always "behind the scenes" updating their games. The bots and plugins have to be updated with them. Just be patient when a patch/hotfix comes through on Diablo, because Demonbuddy (and associated plugins) take a little bit of time to be updated (never had to wait longer than 24 hours) to go with it.
Most profiles are 90%+ afk'able. You might have trouble with some of the questing ones (Act 1 is especially tough at the moment in certain spots), but if you're only concerned with bounties & rifts, then you won't have much of a problem at all.
It's well worth the $31.37 (USD conversion rate at my time of purchase) if you plan to stay with D3 for awhile.