Re the bars--if you don't like them after a while, look into salsa cowchippers, which have a good amount of flare out, or even their cowbell model, which has just a bit of flare. I have cowbell on my Troll and they work great for me.
Trp mechanicals are supposed to be easier to set up than my bb7 avid mechanicals, all I can say is that it comes down to learning new stuff about how to deal with the few pain in the keester aspects of discs, so read up on them, watch YouTube videos and play around with taking the pads out, putting them back in etc.
I'd say the main thing is how small caliper adjustments and even tiny wheel placement differences can result in pad rub on disc, something we aren't used to with rim brakes.
New bunch of stuff to learn basically. Can be frustrating at times. But they do brake really well, especially loaded.