Well If you have read everything you can find about these machines, I really do not know what more you want out of us. I will take a swing though.
Buy the BDB.
In addition to what Bob said, I also think it is the best bang for the buck if you want an easier learning curve. This is just my preference but there is no surfing to find a temperature, you set the temperature and the temp you see is what you get. Temperature changes are stable, there is no offset to calculate, they happen quickly and they are easily repeatable. It makes figuring things out pretty easy and I think that made a big difference for my learning curve.
As I see it, the maintenance things you see on here, changing O rings, steam ball valves, are for people who want to avoid a warranty claim OR do not want to send their machines in to Breville for the paid service. You good sir would have 3 options: use your 4 year warranty, do DIY repairs, or pay for Breville to make repairs.
just my $.02