so milo, what did you decide?
I have been trying out trekking bars for the last month or so and they are better than I thought.
I think its fair to say that for riding on a lot of rough surfaces and low to medium speeds, they seem to me to be a pretty good option. The main disadvantage of them compared to drops is with big headwinds, properly set up drop bars that you can comfortably ride in the drops are going to be more efficient with an unpleasant day of headwinds.

In my case, the bikes I have tried the butterfly bars on already had trigger shifters so it was a fast and easy tryout, I didnt have to buy anything and didnt even have to change the housings, so it was just a matter of slipping the things off the riser bars and onto the trekking bars.