Pneumant wrote:There is no disadvantage to using DT shifters at all.
It's actually the opposite.
Simple situation: steep downhill and sharp left (or right, assuming you have full visibility) turning on a lane that reveals been steep uphill. You hands are on both brakes and you may be signaling the change of direction.
With STI's you can brake AND change gear with the hands in the same position. With DT shifters you have to take one hand off the brake, or leave the shifting at the last moment, likely being already on the uphill thus stressing the chain and sprockets.
This is a very typical scenario when negotiating with uneven terrain, not just off-road but also bridleways, loose road surface, tight hairpins at speed, and the likes.
I do agree about some of the advantages, and I'll add that DT shifters make for packing a bike a lot easier, especially "rinko style"https://janheine.wordpress.com/2016/07/08/how-small-is-a-rinko-bike/
Pneumant wrote:IMO more comfortable brake levers.
Very debatable. Maybe for people with small hands, but the ones with medium hands would already find the cross section of the hoods -in a brake only lever- very thin, this creates a pressure point on the hands. No surprise that STI type levers have gone to a much different shape during the years, modern ones being very forgiving about this.
Pneumant wrote:plus you can operate both levers together with either hand. Just try attempting that with STI's!
That would take a lot of skill and well-adjusted DT shifters, because the Lh and Rh would often have a different ratio in regards of the FD or RD so they end up being stiffer or lighter in one of the two. In a typical scenario of approaching a hill, with DT shifters the Lh lever goes down to the front (to drop in the small ring) while the Rh lever goes to the back (to engage bigger sprockets), the span between the two can be too big to be operated with one hand.
While on the other hand (pun intended) with STI's you have everything on hand already, i.e. with Ergopowers push the buttons on both sides and voilà, small ring and two or three bigger sprockets are engaged in one second.
It is no surprise that STI became popular almost right away, especially during the heated moments of a race, being able to change gear without the obvious movement of the hands down on the frame, is a great advantage both climbing and sprinting.
I do use DT shifters, and very happy with them, but certainly won't use them in all situations, STI's/Ergo's do offer a no-brainer approach because the hands would not leave the bars and the brake levers in critical situations.