Still use bar end shifters on both our tandem and my single racing bike.
Used STI for several thousand miles, it was too finicky (triple on tandem); also test rode the DI-2 electronic system when it first came out and it quit on us in the middle of a tough hill climb after only 1,800 miles of usage.
Switched back to 9 speed barcon shifters (Shimano) and works great.
First generation stuff usually has some issues and the prices can be exorbitant.