I tried the position when riding home yesterday. I can control the bike fine with my forearms resting on the drop bars and my hands together out in front. So I'm not too worried about the control issue, more about having hands so far from brake levers.
Not a problem for me, I always have two feet on a brake.
the additional mounting positions would be a welcome change from the damn oversize drops I have - my light fitting is bodged in a less-than ideal position. I could move it to the aerobars, ditto computer.
http://www.greenbank.org/bikes/tempo/tempo6.jpgGPS goes on end of aero bars.
Routesheet holder goes on one arm of the aerobars (don't use it now but carry it in case GPS stops working).
Computer (Cateye Velo
mounted right at the end of the stem (between the aero bar mounts) using zip ties.
Lights (Solidlights in this picture) mounted on Minoura Space Grip hanging down from aero bars.
Position is fine for long distance, but that's probably because the handlebars were too low for long distance on their own. I got a bit of bach ache on a 600 when I didn't have them fitted. The new bullhorns give me a slightly higher position compared to the hoods on drop bars.