Re:
I don’t know how reliable some of the new road disc brakes are – don’t have them, but suspect they work perfectly well and are reliable. Have used MTB discs for years and never had a problem. My latest MTB (from 2012) has Shimano disc brakes and has been bombproof – apart from occasionally examining / replacing the pads have had to do nothing.
MTBs have their place touring but it all depends what you want to do and where: not as comfortable and less quick. Long distance comfort and stability are important to me, hence the set ups I have. I do have an old Dawes Galaxy hanging in the shed from 1979, was great for many years but the ones I use now are lighter, more comfortable and I’m happy to spend all day on them.
But, MTBs can take you to places that nothing else will and they're a lot of fun. In September went to Georgia (being old and retired has it’s advantages) and cycled from Tbilisi to Tusheti in the Caucasus and back, over some big passes and took the MTB. Some difficulty finding a suitable rack (eventually went with Thule, brilliant) and significant weight (best part of 30 kg with bike, racks, camping gear and food supplies) but was able to get up and down anything, albeit sometimes manhauling the bike up the steepest passes. In descent the bike, and especially the disc brakes, came into their own. Photo shows the bikes and how they were packed.
Coming down the Datvisjvari Pass we cycled downhill for 45 miles, at first very steep and rough, hitting just under 40 mph, and always felt secure with the brakes. The photo shows the view from the top, the descent was one of the most exhilarating things I've ever done on a bike and was fair payback for the long ascent.
Use of dynamo hubs a personal thing. These days I use a power bank to recharge the Garmin, phone and LED lights: in Georgia longest time between electricity to charge devices was three nights and it worked fine – I’ve read elsewhere that people use them to power devices while cycling.
