A lot depends on your headset. If you have a large stack headset (like a Campy Super Record), the threadless adapter and stem will look out of place, IMHO. If you have a low profile type headset, then it might look OK.

As for how they are, with 1 adapter, you can have any bar and stem you want! Compact FSA Omega bars, super light Deda bars and stems, etc. You just have to like the look of a modern stem with a vintage bike.