Dura-ace 9-speed shifters can be used with any other Shimano rear derailer for 9-speed. You can also use them with an old Dura-ace derailer (7400.,7401,7402) to get 8-speed.

I have a bike with STI and a bike with bar-ends. I prefer the bar-ends. One think I don't like about STI is that is takes multiple lever deflections to shift more than one cog smaller. Thus, it takes a little longer to get to the desired gear when dropping down from the big ring, e.g. going from 53/19 to 39/15.

STI is also less reliable. My STI levers are only 5 years old and have started acting up lately. My downtube indexed levers are nearly 20 years old and they still work fine.